Igneous Rock Textures & Classification Based On Grain Size & Shape- Igneous Petrology #2 | GEO GIRL

This video covers how to classify igneous rock textures. We talk about what igneous textures are, why textures are important for igneous rock classification, the difference between igneous structures and textures, how the thermodynamics of crystallization controls igneous rock textures (bowens reaction series, gibbs free energy, enthalpy, entropy, reaction spontaneity, & metastability), how nucleation and growth rates are dependent on ion diffusion rates and how they control grain sizes in igneous rocks, how to classify igneous textures based on grain size (phaneritic, aphanitic, pegmatitic, glassy), how euhedral vs anhedral crystals form, and how to classify igneous rock textures based on grain shape (porphyritic vs vesicular).
References: Essentials of Igneous Petrology by Ronald and Carol Frost: amzn.to/37Zs9AL
Earth Materials by Cornelis Klein and Anthony Philpotts: amzn.to/3z5sCxe
GEO GIRL Website: www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!)
0:00 What are igneous textures?
0:54 Igneous textures vs. structures
1:07 How rocks form textures
3:14 Gibbs free energy & crystallization
7:40 Is crystallization spontaneous?
10:04 What controls crystal size?
14:27 Grain size rock texture classification
17:48 What controls crystal shape?
19:42 Grain shape rock texture classification
20:58 Upcoming content!
22:19 bloopers!
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www.yosemite.ca.us/library/geo...
i.pinimg.com/originals/6e/d3/...
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[@paraskevasskiadopoulos7289]

You are doing such a good job at explaining everything and judging by how much work you put in each of your videos you must really like what you do. I am currently doing my major in geology and until i stumbled upon your channel i wasn't sure if i wanted to pursue a geologist career, but watching your videos is starting to change my mind. As you said in a previous video, its hard to find information on KZbin about geoscience compared to the other sciences and you are doing an amazing job filling that gap. Please keep it up and never lose your sweetness. Thanks for everything. 😊

[@GEOGIRL]

Wow, this comment made my day! I am so happy that my videos can help convince you that geology is AWESOME! And a great path to pursue! ;D Thanks so much for commenting this, I hope my videos continue to be a source of both information and inspiration for you! ;)

[@reshavgupta1172]

@@GEOGIRL Ma'am kindly provide your ppt in downloadable format as well. will help us revise lectures at a faster pace.

[@louis9116]

Out of all the online resources, you explain these topics the BEST! Even though I don't major in this area, I am more and more interested due to your explanations.

[@GEOGIRL]

Wow thanks so much for commenting this, it made my day! So glad you have become more interested from my explanations even though you are not a geo major! ;D

[@marcosjimenez616]

Thank you so much for your well explained lectures! You helped me get through mineralogy last semester and now helping me through petrology. Keep up your great work!

[@slimgrandy9927]

This awesome Geo girl pushing me through college like, Yaaay!... 🙌

[@GEOGIRL]

Yes! So glad to hear that my videos have been helpful for you! Best of luck with the rest of your classes, and let me know if you want any specific topics for future videos ;)

[@javier090994]

I don´t know how I could do my Master's without your videos, thank you!!! Great explanation of everything!!!

[@GEOGIRL]

I am so glad that you've found my videos helpful! ;D

[@the_eternal_student]

It is interesting what gets a student to take interest in a subject. When you said thermodynamics, I got interested, because I recently heard that thermodynamics affects the direction of our perception of time.

[@marc-oliviernollet2472]

I love the porphyric textures. it is very mesmerizing to think about the way they where formed.

[@rebeccameunier-mandar7289]

Thank you for your videos! Not only do you explain the concepts well, your slides are visually representative of each topic (they are also very colorful and not boring to look at). Truly appreciate your work! Thanks :)

[@zacharyrhinelander5055]

Outstanding work on this lecture! I agree pegmatitic🥇 For me it's the purple lepidolite of the Harding mine NM

[@anarcho-geologist4528]

What an excellent video! Thermodynamics is always tricky to review let alone teach! Well executed! Im going to use this video as a review in the future. Your command of the various albeit disparate geology sub-disciplines continues to amaze! I’d have to say my favorite igneous texture is typical phaneritic texture. The typical texture of granite and granodiorites, rocks I’m currently working with! I like the juxtaposition of euhedral grains of plagioclase displaying oscillatory zonation against a fine-grained matrix. I’m vanilla, what can I say…….. EDIT: actually rapakivi granites are gorgeous nevermind I’m not that vanilla after all…

[@GEOGIRL]

Haha! Anything but vanilla I'd say! Great choices! ;D And thanks so much for the kind words about the lecture, I am so glad you thought it was good, it always means so much coming from real geologists! :)))

[@KerriEverlasting]

I'm in awe of this comment. 😂💖

[@barbaradurfee645]

Good summary!

[@akash.sarkar]

Thank you,, great understanding 😘

[@Joseph-gc2kw]

I absolutely love your passion. You explain everything in great detail and I'm understanding the information presented in class much better. Minerology was a bit rough, so I'm definitely trying to recap and continue to learn. Fortunately right now Petrology has been alright. But again, these videos have helped so much. Thanks you again!

[@jasonblack6142]

I've been working with granite for 20 years and 16 different granite shops I've seen a lot of cool Stone coming through the place

[@isacbrito5065]

Great video your channel is the best! Watching from Brazil im studing for a public exam for a geology job

[@lethargogpeterson4083]

I'll go with pegmatitic, too. I once saw a large (5 foot) boulder in a park that was course grained like a normal granite or something (I'm no expert), but had these wonderful inches long orangish pink (orthoclase feldspar?) crystals embedded in it. So cool.

[@basil6276]

Wonderful video, I guess we need the second part of igneous textures to cover more of the textures in igneous rocks under a polarizing microscope

[@jakujaks9413]

You are the best, Thank you Rachel

[@GEOGIRL]

Thanks so much! I am so glad you enjoyed the vidoe ;D

[@jakujaks9413]

Lovin it can't get out.

[@JoesFirewoodVideos]

Yes back to rocks 🪨! Time for me to watch and learn something new! I❤️GEO GIRL PS save your biology videos for your BIO GIRL channel

[@GEOGIRL]

Haha, they aren’t biology videos, they are geobiology! And they are no where on YT so I have to talk about it lol. Besides it’s the only way I can get to astrobiology/geology on my channel, so be patient ;)

[@georgestewart9001]

real good video about geology and i like your lectures

[@GEOGIRL]

Thanks! So glad to have you in my community ;D

[@hossainamini3970]

These video was really useful and helpful. Thank you very much!

[@GEOGIRL]

Thanks! I am so glad to hear that ;D

[@dielauradie]

Great work again! Thank you.

[@GEOGIRL]

Of course, glad you enjoyed! :D

[@HoboMinerals]

Literally, thank you for all of this!

[@GEOGIRL]

Of course! So glad you found it helpful ;D Thanks for the comment!

[@adamc1966]

I've got a big collection from the volcanic areas in California. Even have some pillow basalt.

[@luisfelipegeofisica]

Loving ur classes!

[@GEOGIRL]

Thanks! So glad you like them :)

[@CaptainMir]

Nice 👍 video

[@jasonblack6142]

New subscriber here looking forward to seeing you and your mind .

[@somrinzi]

hey, am enjoying your videos. makes me laugh when u cannot control few laughs ..lol. great content. keep posting more!!!!!!

[@GEOGIRL]

Wow, thank you so much for the encouraging comment! I am so glad you like my videos and share a laugh or two with me ;)

[@KerriEverlasting]

Gibbs free energy! Wow. It has a name!! The chemical bond I asked about in the beginning oh I am stoked, this is amazing 💖

[@GabrielMercier-ue9gs]

Thousand thanks for your fantastc videos. Just a trck for long words, just consider them to be two words or more. I am sure you can say inter and stitial and that you can say one after the other.

[@matthewgardenstheglobeboec7153]

Hi Geo Girl, So what accounts for Spherulitic growth in Felsic Rhyolites? The literature says they ate 'common ' in glassy rhyolites, but what I observed is 'if you find them at all-they most likely will in igneous glassy rocks' which make them Ultra rare and not common at all. Add insult to injury and although these rocks are Felsic ( basic) they are dark colored as if they are Mafic??!? after initial nucleation around a we'll formed Crystal in the melt the sperulites grow outwards in chain connected mers ( polymers) and can be Crystals of Quartz and Crystals of Felspar Polymeric growths and I have heard of quartz/ tourmaline spherulites too. Microscopically the border materials are not glass or glassy and don't break like glass but are something fused together and mostly non fracturable. I'm totally perplexed! Matt in San Diego

[@geologist803]

I was wonderin if u can contine talking about the other texture like amygdaloidal texture and poikitic and ophitic and sup ophitic etc...

[@1forphotos861]

I follow u on Instagram. Thanks for sharing the lectures slide on Instagram. It really helps a lot. Plzz always post the slides. Thank u

[@GEOGIRL]

OMG, I am so sorry! I get on instagram so rarely (I am so bad about that), I promise I will catch up on the ones I am behind on soon! Thanks for letting me know you like the insta posts, that gives me much more motivation to go post them haha! ;)

[@trilochankumar8533]

Mam u are super , amazing lecture in simple way is very rare...thank ❤❤❤ u

[@GEOGIRL]

Aw, this made my day, thank you so much!

[@trilochankumar8533]

@@GEOGIRL you are always welcome mam, keep uploading video..

[@BrunoCassivi]

Gr@titude ❤🎉❤

[@bhatnaseerabn6389]

It is too good, but ur loughing is so gorgeous 😍, i really liked it 💖💗☺

[@GEOGIRL]

Aww thank you, you're too sweet! ;)

[@bhatnaseerabn6389]

@@GEOGIRL most welcome, i need some concepts regarding wiith crystallography

[@GEOGIRL]

@@bhatnaseerabn6389 Have you checked out my mineralogy playlist? I have a couple crystallography videos over there ;) kzbin.infoplaylists

[@sjgeo691]

Great video :)

[@GEOGIRL]

Thanks so much, glad you enjoyed it!

[@sjgeo691]

@@GEOGIRL you do an amazing job with this channel it's incredible how much you have helped me with concepts that I didn't fully understand before

[@GEOGIRL]

Awww that just made my day! Thanks so much AGAIN! I am so glad to hear that, it’s my entire goal with this channel👏🏼😊

[@PhilEbel]

Did you ever work with Shrinermaker (sp) diagrams? Geology is not always described by math or chemistry, but by objective .field observation, Ask the old and dead geologists who found mines and oilfields. And by the way, how does quantum mechanics enter into your lecture?

[@haipo9431]

Hi, how we know igneous rock texture by the composition anortite & albite (diagram phase) ?

[@GEOGIRL]

HI there, I actually have a video all about how we predict igenous rock composition and texture by phase diagrams: kzbin.info/www/bejne/nabIdn2Am5uMma8 Hope this helps ;)

[@222foont]

I'm strangly arroused...Gneiss! (Even though I understood schist!)

[@HoboMinerals]

Can an ultramafic rock continue to grow on the surface, after it’s been cut??

[@deborahkaelin6636]

It's quite funny, in German "Struktur" refers to the small scale properties of igneous rocks, whereas "Textur" is the large scale characteristics (foliation, lineation etc.)

[@GEOGIRL]

Oh wow, that is funny! Haha ;D

[@Enkaptaton]

Listening to English geology as a German is quite fun anyway. Too bad the Feldspat lost it's T in translation to feldspar. I wonder how then this strange word "feldspathoid" came into beeing.

[@shanmugapriya3899]

She:Again however I'm sorry... Me: pls proceed 😅..fortunately I'm getting your point

[@hh924]

Where can i take your slides ? 😍❤️❤️❤️

[@jasonblack6142]

Im off to a place called eastfork in ameila oh

[@rutejraut5557]

Btw you are so beautiful 🤩🤩🤩❤️❤️❤️❤️❤️❤️ 😅

[@GEOGIRL]

Thank you ;)

[@MdSuraf-kk4fc]

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