Rock Identification with Willsey: Intro to Metamorphic Rocks!

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Great series! You are doing what YouTube was made for.

Thanks for these ID videos. They are immensely helpful to amateurs like myself.

Loved this series! This is so much more helpful to me than what I get from written guides, alone. Many thanks!

Another great presentation. Thank you Prof. Willsey!

I've been following this rock Id series. I found this explanation of metamorphism exceptionally clear and easy to understand. Thankfully I have put the id videos into their own playlist. It has been awhile since I did the first videos. I'm discovering that I need to go back and review them. Old brains I find need more repetition. I'm trying as I watch geology videos to pick out the types of rocks on my own. I'm currently enjoying your Iceland series. Any new videos, such as this one I will watch as soon as I can each day. Thanks.

Thanks for showing this Willsey. One key word to remember with metamorphic rock is compression. These rocks are under the earths surface and layers have crushed them over time and weathered them to change them. An example of metamorphic rock is coal when coal was formed it started out as peat you compress peat you get lignite, you compress lignite you get bituminous, and you compress bituminous you get anthracite. One more step is needed to turn coal into a crystal it needs to be heated close to the melting point but not enough to destroy it because when anthracite is heated and compressed it turns to diamonds and thats how they find them. Same process happens with quartzite crystals before that they were sandstone it all has to do with compression.

Thanks! These bite sized lessons are great! Good to see the story behind the rocks out there.

Thank you for your videos Shawn!! ❤

You are just perfect teacher! It is so awesome that I can be your student, although I live on the opposite side of the planer (: My country Estonia has an issue with metheorites - we have lots of impact places. One of them created an island - Osmussaar ( locals called it "grave of Odin"). On the island we have huge pieces of brecha created by the impact, and as a further consiquence - all limestone island is covered with huge and long quarcite "networks" with pyrite and fossils right under your feet.

Yessir - the story is the thing! Thanks!

Yay! Totally awesome. Makes my head spin. 😂 Makes me more a better interpretive guide. Thank you, Shawn.

Ah ha! Low, med, high grade! Important pieces to remember. Hopefully one day I'll pick up a rock and read it. Correctly. You're a great teacher. 👏🏻 Thank you!

THANK YOU VERY CLEAR TEACHING!

I'm a subscriber and absolutely love your amazing videos! I love hiking and have visited many national parks, and I have a great need to understand everything about the rock formations, and your videos really help me have better understanding of these formations before and after my trips! So, thank you so much for sharing your passion and knowledge to help us have greater appreciation for the geological wonders of our earth!

Very interesting! That was a lot great info, gave me a much better picture of these types of rock!

Love your knowledge and I’ve learned so much looking forward to going out and identifying earth processes near me. Thanks Shawn

You have a way of explaining these complex processes and making them so understandable. I have interested in the more complex Geological Processes and you have made them so understandable. Now I know why and how North Carolina and Virginia have such beautiful Gneiss. What is also interesting is that most Igneous rocks on the US East Coast have undergone some kind of Metamorphosis.

Thank you so much Shawn for these videos. I've been looking forward to this one because I find metamorphic rocks quite interesting. Now I have a question that I hope you can answer or lead me to a source for further information. Keep in mind, geology is just a hobby and I have no formal science background. I have several samples of foliated gneiss. I understand that the pressure is forcing minerals (especially columnar types) to line-up perpendicular to the stress. What I can't seem to wrap my head around is why the randomly distributed minerals will separate from each other, then recombine with common minerals to form the banding. I have samples where the biotite is almost perfectly uniform, the white plagioclase and quartz seems to be another band and then even a clear band of almost pure pink K-spar. I just don't get it. How is this occurring? I can't understand how the pressure would cause the minerals to literally change location in the rock and group together. Maybe I'm dense (like a metamorphic rock) but I'm lost. Perhaps you can explain this in the next episode. I would welcome any input from other viewers. Again thank you for your hard work.

Gneiss video. Thanks Shawn.