Cool outcrop near Twin Sisters (City of Rocks, Idaho) exposes the interplay of two granites.

[@TheKrisg50]

I’m loving these videos. It’s humbling to think how long that schist has existed. It was old when Pangea formed. Amazing.

[@shawnwillsey]

Awesome that you found some of these nice gems in the archives. Yeah, these ancient basement rocks predate at least two supercontinents, Pangea and Rodinia. Cool stuff!

[@marklang5169]

Interesting field trip. Thanks for taking us along.

[@Anne5440_]

What great examples of the two ages of granite. Also, In the intrusion of the younger into the older. Earlier tonight, I watched another video of City of the Rocks. Then I just finished the section in your geology underfoot book on the City of the Rocks. Then I watched this video. As I had hoped, watching then, reading about the area is helping me understand better. The book discussion of plutonium and batholith helped straighten out my confusion about the two terms. I began thinking the two words were close to interchangeable. By explaining the size difference, I hope to keep my mind straightened out. Now, I have a place to refer to if I forget. I will try to grab my notebook tomorrow and write this out. (Retired teacher here, my masters was in education. ) This using different resources, videos, books, and writing notes has worked well for me in the past. Having looked at the pictures of the granites in the book closely helped me remember you pointing out the minerals and crystals in the id videos. This is helping my desire for deeper knowledge. Also, part of my biology minor had been a class in trees. I had never heard of the mountain mahogany before. So I dug into that a bit. It apparently isn't found in Washington state. So I'm learning trees in Idaho more. Thanks for teaching this "old dog."

[@farrendavis4143]

Shawn, these are GREAT videos! i can actually talk to my geologist daughter about the amazing formations in Idaho!

[@shawnwillsey]

Awesome! That's what its all about. Enjoy the existing videos here and look for more soon.

[@Josh-Hunt]

Love your enthusiasm!

[@terryhunsaker8317]

Thank you for your videos. I know nothing about Geology other than what I have learned on your site. You are a wonderful teacher. Keep up the good work.

[@sharonlobo7930]

Incredible! Thank you.

[@loranelflatz2989]

My husband and I are really enjoying your geological descriptions. Thank you so much for sharing your expertise. Any chance you will be doing one explaining the honeycombs in Leslie Gulch?

[@shawnwillsey]

Thanks for your kind words. I am not familiar with the honeycombs in Leslie Gulch so let me know more please.

[@loranelflatz2989]

@@shawnwillsey I think you would really enjoy seeing it. Leslie Gulch is in the Owyhees. You take a road North of Jordan Valley, Oregon. If you come to Boise, we would be happy to take you.

[@BobKeefe]

We’re wintering out west, hiking and wondering about the rocks we see. We found your videos and are seeing the rocks with new eyes thanks to you 😃 I find it humorous that even rocks engage in May-December marriages 😆

[@shawnwillsey]

Hi Bob and thanks for watching. Glad you enjoy these. Let me know if there are any areas you want covered. I've got some travelling on my schedule this spring (AZ, UT, NV) and will add some more to the collection.

[@DavidHuber63]

Definitely cool 😎 👍🏼♥️

[@muzikhed]

Wonderful. The time line for the two Granits is awesome yet superseded by that Schist zenolith which after all that time is still there to admire. A rock is like a page in the book of Earth history....so cool. Do you have a favourite rock?

[@shawnwillsey]

Yeah this is one of my favorite places in Idaho. Idaho's youngest and oldest granites, side by side. Jeez, favorite rock? Such a loaded question. For sed rocks, I like conglomerates the most for the power of water they signify. For igneous rocks, probably tuff, again for the power of an eruption. For metamorphic rocks, I like quartzite. It's so durable and timeless.

[@56NeilWatson]

That slab looks interesting

[@jackprier7727]

Impressive huge feldspar crystals in the Archean pluton, shocking to see an ultra-ancient schist xenolith caught up in the 2.5billion y.o. stuff-

[@shawnwillsey]

Love this area. Awesome geology. Glad you enjoyed it as well.

[@pmm1044]

Way cool

[@telejayanderson]

How great to make a video where you get to say "piece of schist" in a serious, academic tone. Thanks for furthering my understanding. I climbed on the old rock at Jackson's thumb and learned that it is slicker even though it has those big crystals.

[@shawnwillsey]

Thanks for your comments. Yeah, the old granite climbs very different than the younger granite.

[@kevindorland738]

Is the biotite mice hard enough it weathers away at a slower rate?

[@shawnwillsey]

It's a pretty soft mineral. Also the iron in biotite is prone to oxidation which increases the weathering rate.

[@tomkrzyt]

I heard that large granite crystals suggest that intruded magma cooled very slowly. Is that true?

[@shawnwillsey]

Yes, in general, larger mineral crystals in granite result from slower cooling rates. The presence of more water mixed in the magma can also produce larger crystals.

[@Don.Challenger]

Presumably, those tiny trees rooting themselves into the clefts in your granites are pretty old, though probably not into many hundreds of years. I mention them as possible grasping points if you end up tubing down a rock face without the tube which I've found much more exciting though always accidental.

[@3xHermes]

👍