Even though i know nothing about geology and mineralogy i learned a lot from this video. I live in Greece, on the island of Syros which is full of geologic treasures all around. I became interested on these topics once i started discovering interesting rocks. I've collected so many speciments that i still need to intentify and i have to say im having the time of my life. Keep making awesome and educating videos!
Aw thanks! I am so glad you found the video helpful and I am also so happy you are having a good time collecting and identifying rocks! Of the ones you have identified what do you have? And which is your favorite?? ;D
The ones that i have identified are quartz, marble, and recently serpentinite. We have many types of interesting eclogites which i do not know the exact names of but ive currently located about 3 different kinds. My favorite is a black eclogite on the northern side of the island called locally Aerolithos. Its a metamorphic rock (i believe) and it contains tiny little black crystals. Ive also found a small octahedron shaped crystal with a silver color. Still lots to intentify. Im also looking for garnets on the island, I heard they exist but i havent located them yet.
Another very interesting and outstanding video as usual my friend. I always feel more and more educated after watching every incredibly fascinating video that you make. As usual, it’s always such a tremendous pleasure for me to learn with someone as beautifully gifted and intelligent as you my favorite teacher. You’re the best. 😊❤😉👍
@@GEOGIRL You're very welcome my friend. 😉 I’m so glad my support is what keeps you going. You’re videos never disappoint because you always make the best content and I hope you never stop. 😊 You’re absolutely amazing Rachel. ❤👍
Nice video! I love the detailed explanation of all of this. I could never absorb all of this information in my old brain. It's hard enough to remember all of the rock names themselves! All of this has me feeling a field trip coming on. I am in East Tennessee, so I have access to some of these over the mountains in Western North Carolina and South Carolina.
Learned a lot from this video. Gives me more of an understanding of the composition of the Paloma Valley ring complex that my neighborhood is next to. The info on epidote occuring near most likely crystalline quartz and how it can morph into garnet really helps on my rock hounding missions. I've found smokey quartz, quartz with chlorite or epidote inclusions and attachments, black tourmaline, and a few chunks of pyrite. Still hoping to find some garnet or allenite.
Cannot be more eternally grateful for this content, having synthesized most of my metamorphic petrology semester materials in 30 minutes and also clearing out some of my questions! Greetings from a future exploration geologist in Bulgaria! :)
Yes, you were correct. I did notice the "less exuberant" attitude towards this topic versus others, and that's okay. It's better to give your presentations with your genuine inflections than to try to force excitement that isn't there, because that is noticeable as well. As an aside to that, when it comes to topics that aren't personally exciting to you, such a petrology or metamorphism, you may be able to include parts of the topics you do enjoy, like historical geology or marine depositions to explain geologic formations or times when certain metamorphic events have occurred. For example, the different terranes and orogenies of the northeast offer many examples of basalt metamorphism that can be correlated to certain orogenic events. My apologies for rambling on. You do well with your presentations and I enjoy them however you present them !
That's a great idea about including parts I enjoy! Thanks ;D I think I just subconciously categorize my videos into 'appealing to many' or 'appealing only to students who want to pass an exam' but then I forget that I can make the latter more interesting if I wanted to by bringing in other info like you mentioned :D Thanks for the suggestion and for the support no matter what, you are the best! ;)
Nice video. So refreshing to find a good geoscience channel. How far are you with your PhD? I recently completed mine and I am doing some part time lecturing. Your videos are a good benchmark for how to keep an audience engaged.
Oh my gosh! CONGRATS!! 🎉 And thank you so so much for saying that, I am so happy you enjoy my videos ;D I am a candidate but still have ~3-4 semesters to go :) What was the topic of your dissertation?
Thank you! They really are great videos. I hope the remainder of your project goes well. I can tell you clearly have strong motivation and emotional investment in your work, so I am certain you will produce a great final dissertation. I hope you have a good supervisor! Keep us updated about your progress! My dissertation was quite multi-faceted, but was primarily a study of the Late Quaternary deep sea sedimentary record of glaciation in Kamchatka and eastern Siberia. What I really was aiming for was to constrain the limits of the Northwest Pacific equivalent of the North Atlantic "Ruddiman" ice-rafted debris belt, which gets much more attention! It ended up being bigger than that with some foram assemblage work, tephrochronology and some geochemistry and XRF looking at sediment provenance, supported by a nice computer iceberg trajectory model. It's freely available online if you want to scan your eyes across it! Link to my thesis: etheses.whiterose.ac.uk/29294/ There is also a related paper in EPSL. My sediments might be a bit recent for your liking though ;)
I came across your channel while searching online about omphacite, and you've got a new subscriber! Excellent video covering topics I knew and also didn't know, good explanations and detail on the cause and processes, keep up the teaching.
@@AgentJRock805 Haha oh my gosh, with those grades you have absolutely nothing to worry about for sed strat! But if you do get confused, you can certainly watch my sed strat playlist for help ;) (And suggest me topics for that playlist early so I can get them out by the time you need them!)
Excellent explanation. I have seen actinolite-tremolite present concurrently/together with prehnite in metamorphosed gabro, as prehnite replace pseudomorph pyroxene and actinolite-tremolite replace matrix on thin section.
Thank you! And cool, isn't amazing how diverse gabbro and basalt (& their metamorphic equivalents) can be in thin section! And the bright interference colors are my favorite :D
@@GEOGIRLback in the day, I was wondering wether there's a control of tectonic emplacement like collision or melange related subduction zone that result in overprinting of prehnite-pumpellyte facies - on green schist facies or it's just product of circulation of sea water on oceanic crust via fractures/faults as a conduit. As that gabro was interpreted as part of dismembered oceanic crust.
Do you keep physical samples in addition to photos? I'm just starting out looking at rocks. I have a mixed bag of rocks and looking at them to figure out what's around me. So I have more questions that answers, looking at the rocks and sorting them out into groups. Neat stuff. Easier to sort by photo, but something seems more human by having something to touch when discerning the differences. Also, I haven't licked them, but something in me just wants to smell, taste, touch, and hear the differences in addition to just seeing the difference. Happy Monday.
I got to this video by reverse image searching some blueschist with a yellow gem looking thing in it. Lol anyways found it at my cabin in cascade Idaho and you may have given me the whole recipe book to the area I rockhound there. Lots of green stuff
Bringing in the 4k energy! This is a topic I know so little about, it's always a full video of new knowledge. You are getting very good at doing these long presentations as well. Do you have any teaching or educational interests beyond youtube?
Thank you so much! Any yes, I absolutely do ;D I am a PhD student right now and do a lot of teaching as a TA (that's why I started posting my lectures on YT), but in the future I hope to become a full professor (and continue to teach on YT) ;)
@@TheRexisFern Thank you so much! I am so happy you enjoy my 'online class' haha! My in-person students don't seem to appreciate me as much as my online student I guess lol😂
Haha I am so glad you found the video helpful ;) If you ever want specific topics that I haven't covered yet just let me know and maybe I can make a future video about it ;D
I really enjoy the content, but I don't understand the waving around of the cursor. When you are speaking of a specific mineral in a thin section but your waving around within the whole area in view, its hard to know which mineral you are pointing at.
Undergraduates are much like cats. If you want to keep their attention on something in a science lecture, sometimes waving around a laser pointer is the only way to keep them from wandering off to take a nap in the sun....
Just finished watching a documentary about Metamorphism, starring Rachel Nasa, and it brought me an annoying existential question. I'll post it in that video, I think it's the best to do so. When talking about pelitic rocks, I understand that the initial rock is very brittle, after all is a bunch of little fragments brought together. Cohesion is small. Same goes for evaporites or carbonates rock. When you put heat and pressure, they will re organize to take an ultimately more stable conformation. However, it doesn't make that much sence (to my personnal actual vision of the world) with igneous rocks. They are born from a very high temperature and pressure medium, so they should be already pretty stable, no ? How come putting a little (somewhat little) pressure and temp increase would make them reform ? Also, the granulite facies is pretty close to what the initial state was, how come would they go throught to all that metamorphism to come back to their initial phase ? I suppose I'm making tons of false assumpions here, perdon my ignorance haha. Thanks again for all that content. You're awesome.
Great question! So it's important to remember that igneous rocks do not *form* at high T, they are the cooled remains of what melted at high T, so they are still suceptible to re-melting if subject to high T again. When they do completely re-melt and re-cool, they are still termed igneous. However, if they are subject to high T that is not high enough to fully re-melt them, it can still cause major deformation and transformation of certain minerals within the rocks. This is because some minerals in igneous rocks/melts will melt/crystallize at lower T than others, so those minerals will begin to convert to more stable minerals at high T (called high T polymorphs). All the while, because pressure is typically high in these environments as well, the minerals that are transforming and recrystallizing are re-orienting themselves along to the pressure axis because they are in a less solid state. From there, if the temperature does not reach a level of fully melting all the minerals in the rock, then the rock will eventually cool and recrystallize and at that point the new rock is metamorphic. Even though metamorphic rocks contain the same basic set of minerals sa igneous rocks (with the exception of the newly formed high pressure polymorphs) we often look to texture to distinguish metamorphic and igneous rocks. Hope that makes sense! :D
@@GEOGIRL So the conditions (P, T) in which the rocks form is actually the real thing to look at in this case ? Does it mean magma has to cool at low temp and low pressure to form igneous rock, otherwise it would create metamorphic rock right away ? And does it mean plutons that created igneous rock are relatively close to the surface so they have this low temp and low pressure range ? Just trying to clarify my mind about this, thanks so much for your help :)
@@pascalsevigny1627 So yes and no, igneous rocks cool from melted magma/lava material, whereas metamorphic rocks are those that form when the material was never fully melted to begin with. Metamorphic rocks start as igneous or sedimentary rocks (or previously metamorphosed rocks) and then get metamorphosed when they are put under intense heat and pressure withOUT melting the material fully. If the material were to fully melt and recool it would then be classified as igneous. Does that make sense?
@@GEOGIRL I Think so. I had some nighmares about this but it's starting to make some sence hahaha. First, not every rock will undergo metamorphism under every conditions. I was kind of stuck with igneous intrusive rocks, such as granite. I understand now that granite won't go under metamorphism easily compared to less stable rock like Limestone, because it's more stable. However, it can still undergo metamorphism given conditions such as high temp combined with oriented pressure, where minerals are not necessarily changing but rather repositioning themselves to make gneiss. I also had problem with the fact that gabbro could undergo metamorphism so easily, since it's intrusive igneous, however I didn't know it was mostly induced by hydrothermal metamorphism, which introduce another chemical factor in the game. As I learn more it gets more intuitive, there are many ways metamorphism can occur. It's very exciting to learn about all this. Thank you so much :)
Do metamorphic rocks play a role in human evolution or was stone technology all about flint, a sedimentary rock? I would have thought that any rock which splits to form razor sharp edges would have been useful.
What a great and valid question! Unfortunately, I have no idea lol! But my hunch is that, even though metamorphic rocks would've been a great option, chert/flint is just so abundant and widespread and sturdy that I assume they would've stuck with it... I mean if it ain't broke, right? haha If you find anything that suggests they used other materials though, let me know! I am curious now ;D
Thanks for the great video. I've got a question to ask. could you tell me the difference between the Basalt rock and Meta-Basalt rock? I know that the meta-Basalt was gone through some metamorphism but it is not quite clear for me.
A basalt is completely igneous, meaning it cooled from lava at earth's surface and did not undergo any more deformation after that. A metabasalt is a basalt that cooled from lava at earth's surface and then underwent additional deformation (metamorphism) later that altered its mineral composition and potentially its texture. This happens because rocks can become buried after formation and then put under extreme heat and pressure either because of very deep burial or because they get caught in a tectonic region undergoing higher pressures due to plates pushing against each other. Hope that helps ;)
hey which book did you read to make this video from? I have geology as my subject and would really appreciate if you let me know for better references and understanding 😄
I don't know if you've watched them, Rachel, but geology professor Iain Stewart ( en.wikipedia.org/wiki/Iain_Stewart_(geologist) ) has hosted several interesting geology TV series that might interest you (They're good): Men of Rock ( en.wikipedia.org/wiki/Men_of_Rock ) - ua-cam.com/video/LaitlLpcDo8/v-deo.html , ua-cam.com/video/yxErRwwzJjM/v-deo.html , ua-cam.com/video/vGnBz0VwXoE/v-deo.html Rise of the Continents ( en.wikipedia.org/wiki/Rise_of_the_Continents ) - ua-cam.com/video/ue2gcyT4fc4/v-deo.html Earth: The Power of the Planet ( en.wikipedia.org/wiki/Earth:_The_Power_of_the_Planet ) - ua-cam.com/video/zHGyU9m7CsI/v-deo.html
Bonjour, j'ai une question, j'ai cette pierre, la gabbro, taille moyenne, intérieur, cristal, mais j'ai un besoin urgent d'argent, je voudrais la donner moins cher, je suis en France, à Pas Sur Fin, près de Nantes.
Bonjour, j'ai un gabbro, je ne sais pas à qui le vendre, et j'ai besoin de l'argent immédiatement, donc je vous proposerais d'acheter chez moi si vous le pouvez, merci beaucoup
A) I have no idea how you've come to have such broad knowledge of geology. Blowing me away! B) The greenstone in Phoenix Mountain area doesn't fit in any likeness of example greenstone or greenschist, based on my very limited time in the field. Likely the formed from the subduction at western Precambrian margin, and that part makes sense. But the subsequent uplift brought about subsequent deformation, but there appears to be dominant platy schist and not greenstone at exposures I've seen, despite my reference manual here -> repository.azgs.az.gov/sites/default/files/dlio/files/nid1110/cm-04-atext8x11.pdf But what does greenschist or greenstone metamorphose into? What does it become? C) I have no idea how you mastered so much geology! Nice channel!
The schist makes sense because the greenstone, if metamorphosed further, would become schist ;) Hope that makes sense! Also, thanks for the kind words, so glad you enjoy the channel :)
Cummingtonite! My favorite name for any mineral. Geological puns ftw.
My dad used to say, "Don't be so quick to find faults".
A good man but terrible geologist!
Hahaha lol I guess you're right, gotta find faults in geology! ;D
Even though i know nothing about geology and mineralogy i learned a lot from this video. I live in Greece, on the island of Syros which is full of geologic treasures all around. I became interested on these topics once i started discovering interesting rocks. I've collected so many speciments that i still need to intentify and i have to say im having the time of my life. Keep making awesome and educating videos!
Aw thanks! I am so glad you found the video helpful and I am also so happy you are having a good time collecting and identifying rocks! Of the ones you have identified what do you have? And which is your favorite?? ;D
The ones that i have identified are quartz, marble, and recently serpentinite. We have many types of interesting eclogites which i do not know the exact names of but ive currently located about 3 different kinds. My favorite is a black eclogite on the northern side of the island called locally Aerolithos. Its a metamorphic rock (i believe) and it contains tiny little black crystals. Ive also found a small octahedron shaped crystal with a silver color. Still lots to intentify. Im also looking for garnets on the island, I heard they exist but i havent located them yet.
Another very interesting and outstanding video as usual my friend. I always feel more and more educated after watching every incredibly fascinating video that you make. As usual, it’s always such a tremendous pleasure for me to learn with someone as beautifully gifted and intelligent as you my favorite teacher. You’re the best. 😊❤😉👍
Thank you as always my friend, you keep me going! :D
@@GEOGIRL You're very welcome my friend. 😉 I’m so glad my support is what keeps you going. You’re videos never disappoint because you always make the best content and I hope you never stop. 😊 You’re absolutely amazing Rachel. ❤👍
Thanks for this video. Lots of greenstone near where I live in the Smartville Complex. Crazy to see pillow basalt in the mountains 🥰
Great content. Would love to see hand samples of the rock that each of thin sections were prepared from.
Nice video! I love the detailed explanation of all of this. I could never absorb all of this information in my old brain. It's hard enough to remember all of the rock names themselves! All of this has me feeling a field trip coming on. I am in East Tennessee, so I have access to some of these over the mountains in Western North Carolina and South Carolina.
Learned a lot from this video. Gives me more of an understanding of the composition of the Paloma Valley ring complex that my neighborhood is next to. The info on epidote occuring near most likely crystalline quartz and how it can morph into garnet really helps on my rock hounding missions. I've found smokey quartz, quartz with chlorite or epidote inclusions and attachments, black tourmaline, and a few chunks of pyrite. Still hoping to find some garnet or allenite.
Cannot be more eternally grateful for this content, having synthesized most of my metamorphic petrology semester materials in 30 minutes and also clearing out some of my questions! Greetings from a future exploration geologist in Bulgaria! :)
Super cool to hear about the zeolite! We use it for VOC adsorbtion.
Excellent video as usual! Basalts are abundant here on Lake Superior and highly underrated in my opinion. 👍
I am sure they are, but if I had to choose between Lake Superior Agates and Basalts, I would still choose agates haha ;)
@@GEOGIRL agreed! But without vesicular basalt we wouldn’t have those yummy striped nodules 🤩
@@botryoidalbishhh3150 True!! ;D
Yes, you were correct. I did notice the "less exuberant" attitude towards this topic versus others, and that's okay. It's better to give your presentations with your genuine inflections than to try to force excitement that isn't there, because that is noticeable as well.
As an aside to that, when it comes to topics that aren't personally exciting to you, such a petrology or metamorphism, you may be able to include parts of the topics you do enjoy, like historical geology or marine depositions to explain geologic formations or times when certain metamorphic events have occurred.
For example, the different terranes and orogenies of the northeast offer many examples of basalt metamorphism that can be correlated to certain orogenic events.
My apologies for rambling on. You do well with your presentations and I enjoy them however you present them !
That's a great idea about including parts I enjoy! Thanks ;D
I think I just subconciously categorize my videos into 'appealing to many' or 'appealing only to students who want to pass an exam' but then I forget that I can make the latter more interesting if I wanted to by bringing in other info like you mentioned :D
Thanks for the suggestion and for the support no matter what, you are the best! ;)
I just studied this topic last week :) Fully enjoyed the revision with your video.
So glad to hear that! What great timing ;D
Interesting rock 🪨 all of them
Which one? haha
new niche hobby acquired! Thanks for this explanation.
Nice video. So refreshing to find a good geoscience channel. How far are you with your PhD? I recently completed mine and I am doing some part time lecturing. Your videos are a good benchmark for how to keep an audience engaged.
Oh my gosh! CONGRATS!! 🎉 And thank you so so much for saying that, I am so happy you enjoy my videos ;D
I am a candidate but still have ~3-4 semesters to go :)
What was the topic of your dissertation?
Thank you!
They really are great videos. I hope the remainder of your project goes well. I can tell you clearly have strong motivation and emotional investment in your work, so I am certain you will produce a great final dissertation. I hope you have a good supervisor! Keep us updated about your progress!
My dissertation was quite multi-faceted, but was primarily a study of the Late Quaternary deep sea sedimentary record of glaciation in Kamchatka and eastern Siberia. What I really was aiming for was to constrain the limits of the Northwest Pacific equivalent of the North Atlantic "Ruddiman" ice-rafted debris belt, which gets much more attention!
It ended up being bigger than that with some foram assemblage work, tephrochronology and some geochemistry and XRF looking at sediment provenance, supported by a nice computer iceberg trajectory model. It's freely available online if you want to scan your eyes across it!
Link to my thesis: etheses.whiterose.ac.uk/29294/
There is also a related paper in EPSL. My sediments might be a bit recent for your liking though ;)
I came across your channel while searching online about omphacite, and you've got a new subscriber! Excellent video covering topics I knew and also didn't know, good explanations and detail on the cause and processes, keep up the teaching.
This would have been nice last week before my finals. Another great video.
Haha oh no! I am sorry, wish I made it sooner! I am sure you did great either way ;)
@@GEOGIRL Yeah we're good. 98.1 on my lab final and likely an A on my Lec exam. I have the dreaded sed strat next semester.
@@AgentJRock805 Haha oh my gosh, with those grades you have absolutely nothing to worry about for sed strat! But if you do get confused, you can certainly watch my sed strat playlist for help ;) (And suggest me topics for that playlist early so I can get them out by the time you need them!)
#Geo girl.. beautiful look..👌
Thanks ;)
@@GEOGIRL most welcome..🍻🙃🙃
Thanks for all your hard work
Of course! Thank you so much for your support :D
Excellent explanation. I have seen actinolite-tremolite present concurrently/together with prehnite in metamorphosed gabro, as prehnite replace pseudomorph pyroxene and actinolite-tremolite replace matrix on thin section.
Thank you! And cool, isn't amazing how diverse gabbro and basalt (& their metamorphic equivalents) can be in thin section! And the bright interference colors are my favorite :D
@@GEOGIRLback in the day, I was wondering wether there's a control of tectonic emplacement like collision or melange related subduction zone that result in overprinting of prehnite-pumpellyte facies - on green schist facies or it's just product of circulation of sea water on oceanic crust via fractures/faults as a conduit. As that gabro was interpreted as part of dismembered oceanic crust.
Do you keep physical samples in addition to photos? I'm just starting out looking at rocks. I have a mixed bag of rocks and looking at them to figure out what's around me. So I have more questions that answers, looking at the rocks and sorting them out into groups. Neat stuff. Easier to sort by photo, but something seems more human by having something to touch when discerning the differences. Also, I haven't licked them, but something in me just wants to smell, taste, touch, and hear the differences in addition to just seeing the difference. Happy Monday.
GEO GIRL ROCKS!
I ❤️ GEO GIRL!
I love your videos. You definitely contributed to my mineralogy A
YESSS Congrats on your A!! That's all on you! ;D But thank you so much for the comment, so glad you found my videos helpful ;)
I got to this video by reverse image searching some blueschist with a yellow gem looking thing in it. Lol anyways found it at my cabin in cascade Idaho and you may have given me the whole recipe book to the area I rockhound there. Lots of green stuff
Neşriyatlar için çok teşekkürler ediyoruz.
Birşey değil! Yorum için teşekkürler! ;)
@@GEOGIRL
Adınız Cindy Jenny Conner değilmi ?
Bringing in the 4k energy! This is a topic I know so little about, it's always a full video of new knowledge. You are getting very good at doing these long presentations as well. Do you have any teaching or educational interests beyond youtube?
Thank you so much! Any yes, I absolutely do ;D I am a PhD student right now and do a lot of teaching as a TA (that's why I started posting my lectures on YT), but in the future I hope to become a full professor (and continue to teach on YT) ;)
@@GEOGIRL Well I'm very glad to be enrolled in your class! You're obviously the cool teacher on campus! :D
@@TheRexisFern Thank you so much! I am so happy you enjoy my 'online class' haha! My in-person students don't seem to appreciate me as much as my online student I guess lol😂
Looking so beautiful
Thank you ;)
@@GEOGIRL your welcome
You are such a life saver
Haha I am so glad you found the video helpful ;) If you ever want specific topics that I haven't covered yet just let me know and maybe I can make a future video about it ;D
Thanks mam,from long time i was waiting for this.....
You are very welcome, I hope it was worth the wait ;)
Nice explication
I really enjoy the content, but I don't understand the waving around of the cursor. When you are speaking of a specific mineral in a thin section but your waving around within the whole area in view, its hard to know which mineral you are pointing at.
Undergraduates are much like cats.
If you want to keep their attention on something in a science lecture, sometimes waving around a laser pointer is the only way to keep them from wandering off to take a nap in the sun....
Just finished watching a documentary about Metamorphism, starring Rachel Nasa, and it brought me an annoying existential question. I'll post it in that video, I think it's the best to do so. When talking about pelitic rocks, I understand that the initial rock is very brittle, after all is a bunch of little fragments brought together. Cohesion is small. Same goes for evaporites or carbonates rock. When you put heat and pressure, they will re organize to take an ultimately more stable conformation. However, it doesn't make that much sence (to my personnal actual vision of the world) with igneous rocks. They are born from a very high temperature and pressure medium, so they should be already pretty stable, no ? How come putting a little (somewhat little) pressure and temp increase would make them reform ? Also, the granulite facies is pretty close to what the initial state was, how come would they go throught to all that metamorphism to come back to their initial phase ? I suppose I'm making tons of false assumpions here, perdon my ignorance haha. Thanks again for all that content. You're awesome.
Great question! So it's important to remember that igneous rocks do not *form* at high T, they are the cooled remains of what melted at high T, so they are still suceptible to re-melting if subject to high T again. When they do completely re-melt and re-cool, they are still termed igneous. However, if they are subject to high T that is not high enough to fully re-melt them, it can still cause major deformation and transformation of certain minerals within the rocks. This is because some minerals in igneous rocks/melts will melt/crystallize at lower T than others, so those minerals will begin to convert to more stable minerals at high T (called high T polymorphs). All the while, because pressure is typically high in these environments as well, the minerals that are transforming and recrystallizing are re-orienting themselves along to the pressure axis because they are in a less solid state. From there, if the temperature does not reach a level of fully melting all the minerals in the rock, then the rock will eventually cool and recrystallize and at that point the new rock is metamorphic. Even though metamorphic rocks contain the same basic set of minerals sa igneous rocks (with the exception of the newly formed high pressure polymorphs) we often look to texture to distinguish metamorphic and igneous rocks.
Hope that makes sense! :D
@@GEOGIRL So the conditions (P, T) in which the rocks form is actually the real thing to look at in this case ? Does it mean magma has to cool at low temp and low pressure to form igneous rock, otherwise it would create metamorphic rock right away ? And does it mean plutons that created igneous rock are relatively close to the surface so they have this low temp and low pressure range ? Just trying to clarify my mind about this, thanks so much for your help :)
@@pascalsevigny1627 So yes and no, igneous rocks cool from melted magma/lava material, whereas metamorphic rocks are those that form when the material was never fully melted to begin with. Metamorphic rocks start as igneous or sedimentary rocks (or previously metamorphosed rocks) and then get metamorphosed when they are put under intense heat and pressure withOUT melting the material fully. If the material were to fully melt and recool it would then be classified as igneous. Does that make sense?
@@GEOGIRL I Think so. I had some nighmares about this but it's starting to make some sence hahaha. First, not every rock will undergo metamorphism under every conditions. I was kind of stuck with igneous intrusive rocks, such as granite. I understand now that granite won't go under metamorphism easily compared to less stable rock like Limestone, because it's more stable. However, it can still undergo metamorphism given conditions such as high temp combined with oriented pressure, where minerals are not necessarily changing but rather repositioning themselves to make gneiss. I also had problem with the fact that gabbro could undergo metamorphism so easily, since it's intrusive igneous, however I didn't know it was mostly induced by hydrothermal metamorphism, which introduce another chemical factor in the game. As I learn more it gets more intuitive, there are many ways metamorphism can occur. It's very exciting to learn about all this. Thank you so much :)
Thank you
Of course, thanks for watching & leaving a comment! ;)
Do metamorphic rocks play a role in human evolution or was stone technology all about flint, a sedimentary rock? I would have thought that any rock which splits to form razor sharp edges would have been useful.
What a great and valid question! Unfortunately, I have no idea lol! But my hunch is that, even though metamorphic rocks would've been a great option, chert/flint is just so abundant and widespread and sturdy that I assume they would've stuck with it... I mean if it ain't broke, right? haha If you find anything that suggests they used other materials though, let me know! I am curious now ;D
Thanks for the great video. I've got a question to ask. could you tell me the difference between the Basalt rock and Meta-Basalt rock? I know that the meta-Basalt was gone through some metamorphism but it is not quite clear for me.
A basalt is completely igneous, meaning it cooled from lava at earth's surface and did not undergo any more deformation after that. A metabasalt is a basalt that cooled from lava at earth's surface and then underwent additional deformation (metamorphism) later that altered its mineral composition and potentially its texture. This happens because rocks can become buried after formation and then put under extreme heat and pressure either because of very deep burial or because they get caught in a tectonic region undergoing higher pressures due to plates pushing against each other.
Hope that helps ;)
@@GEOGIRL thanks for the great explanation. Could you please give me a good reference for this information?
hey which book did you read to make this video from?
I have geology as my subject and would really appreciate if you let me know for better references and understanding 😄
Hey, all the references used to make this video are linked in the description box! Just check see more on the box below the video ;)
What would a pressure-temperature path on a graph look like for the amphibolite facies?
It's gonna be a clockwise pt graph
Nice bedsheet or blanket
Thanks I love my periodic table blanket so much! haha ;D
@@GEOGIRL i know that ..I notice it many times
Can you explain something about metadolerites?
What would be the predominant rock/rock type in the Mantle?
Peridotite (an ultramafic igneous rock) makes up the bulk of Earth's mantle :)
I don't know if you've watched them, Rachel, but geology professor Iain Stewart ( en.wikipedia.org/wiki/Iain_Stewart_(geologist) ) has hosted several interesting geology TV series that might interest you (They're good):
Men of Rock ( en.wikipedia.org/wiki/Men_of_Rock ) - ua-cam.com/video/LaitlLpcDo8/v-deo.html , ua-cam.com/video/yxErRwwzJjM/v-deo.html , ua-cam.com/video/vGnBz0VwXoE/v-deo.html
Rise of the Continents ( en.wikipedia.org/wiki/Rise_of_the_Continents ) - ua-cam.com/video/ue2gcyT4fc4/v-deo.html
Earth: The Power of the Planet ( en.wikipedia.org/wiki/Earth:_The_Power_of_the_Planet ) - ua-cam.com/video/zHGyU9m7CsI/v-deo.html
Bonjour, j'ai une question, j'ai cette pierre, la gabbro, taille moyenne, intérieur, cristal, mais j'ai un besoin urgent d'argent, je voudrais la donner moins cher, je suis en France, à Pas Sur Fin, près de Nantes.
What about hornfels
fax bro that's what i came here for
I'm first in comment, view and like..
You are the BEST, thank you! ;D
@@GEOGIRL and also you.. Geo girl..🙃🙃
Do you have notes of your these??
Bonjour, j'ai un gabbro, je ne sais pas à qui le vendre, et j'ai besoin de l'argent immédiatement, donc je vous proposerais d'acheter chez moi si vous le pouvez, merci beaucoup
Hello geo girl
Hello there ;) Hope you enjoyed the video :D
@@GEOGIRL yes thank you so much
8:00 dragon fly poop
A) I have no idea how you've come to have such broad knowledge of geology. Blowing me away! B) The greenstone in Phoenix Mountain area doesn't fit in any likeness of example greenstone or greenschist, based on my very limited time in the field. Likely the formed from the subduction at western Precambrian margin, and that part makes sense. But the subsequent uplift brought about subsequent deformation, but there appears to be dominant platy schist and not greenstone at exposures I've seen, despite my reference manual here -> repository.azgs.az.gov/sites/default/files/dlio/files/nid1110/cm-04-atext8x11.pdf But what does greenschist or greenstone metamorphose into? What does it become? C) I have no idea how you mastered so much geology! Nice channel!
The schist makes sense because the greenstone, if metamorphosed further, would become schist ;) Hope that makes sense!
Also, thanks for the kind words, so glad you enjoy the channel :)
Hi. Votre wathsab ?