Rock Identification with Willsey: Conglomerate, Breccia, and Diamictite

Learn how to identify and describe conglomerate, breccia, and diamictite, part of the world of sedimentary rocks with geology professor Shawn Willsey.
Link to PDF of my notes: drive.google.com/drive/u/0/fo...
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College of Southern Idaho
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[@StereoSpace]

A little bit of diagnostics I picked up from Dr David Rogers: If the outcrop is clast supported, it was laid down in a flowing or moving water environment, and as the energy dropped below the level where the water could move them it drops them. The clasts will also tend towards the same or similar size. Think of an ancient river or stream bed. If the outcrop is matrix supported, you're looking at a debris flow, like a slope or canyon wall failure that slides down as a big jumble of rocks and sand and mud, that then solidifies like dumped concrete. You'll usually see a mix of clast sizes, and the clasts will appear to be floating randomly oriented in the matrix.

[@MrFmiller]

Even as a refresher I am reminded of important details and/or presented with new information or information I had previously been introduced to from a different perspective. In either case I keep learning new things.

[@edbaker4260]

Here in Nevada, we have what is called the Alamo Breccia which was created by a large meteorite strike some 270 million years ago. I have seen examples that were cut and polished spectacular, however I have not been able to collect any myself.

[@garryjcarlson]

Where in Nevada?

[@somsackvongsa7077]

@@garryjcarlson look at Google map.

[@mmercier0921]

your programs are incredibly helpful. figuring out rocks is more difficult than astronomy for me. this one in particular helped me figure out a rock that has bothered me for years. most people won't understand, it's a rock thing.

[@shawnwillsey]

Thanks for your comment. So glad to hear that my ramblings are of use. And know that there are plenty of us out there who totally get the rock thing.

[@davidk7324]

Great content, Shawn. One key for me to identify clast types in these conglomerate/breccia samples is the idea of "predominant or predominated by."

[@farmboypresents9977]

Just checked out The Connells! Great stuff I never knew. Looked like a younger Shawn Willsey dancing in one of their videos . Its all about rock around here!

[@DoNotEatPoo]

This answered so many questions about some land in a washy area I recently purchased in AZ that hadn't been infiltrated by humans yet... How ancients got a cement truck out in the middle of nowhere to deliver cement and rock waste (similar to sample at 17:10) , then proceeded to cover it with 10 feet of dirt. Now I understand the Earth had cement and transportation technologies in the ancient times.

[@Rachel.4644]

Good morning Shawn! Yes, valuable content. 👍🏼 You've collected some cool samples. This was fun! Thanks.

[@sanjeevrampalliwar3917]

I have recently started identifying my random rock samples in a scientific manner . I find your videos very informative. thank you sir.

[@shawnwillsey]

Great to hear!

[@tulazaz]

Here in Loudoun County VA near the Potomac River, we have a conglomerate called Potomac Marble, which is what was used to create the pillars in Statuary Hall in our nation’s capital building in DC. However it was recently proven by a local rock enthusiast, who has also written a book about its history, that the Potomac Marble used in the capital actually came from the Maryland side of the Potomac River near here. That side of the river had the convenience of transporting the marble to DC via the C&O Canal back in the day. I find it in various places and creeks around the town I live in. Very rough in the raw, but polishes up beautifully. Easy to find pictures of it on Google.

[@Anne5440_]

Very helpful for me to learn the difference between conglomerate and brecca. I already knew conglomerate. But in Nick's videos I was at a loss when breccas were mentioned I was at a complete loss. This is exactly why I started your identity series. Thank you so much.

[@shawnwillsey]

Glad it was helpful. Look for more soon.

[@rushodai929]

I see conglomerate rocks on the trails and I never thought they were formed naturally. Somehow I thought they threw the stones into cement and broke it up for use as filler rock on the trails. Since I’m always looking down at the trail, these videos help me identify the rocks as more than “ooh, pretty!”.

[@TimT-um6rt]

Great informative video on Breccias!Your knowledge has further explained and defined a occurrence on my turquoise claim in Nev. Black chert clasts with turquoise or other copper oxides as the cementing agent! Unique , I'll try to send you a polished sample sometime! Thanks again Shawn!

[@gwynnfarrell1856]

Nice lesson! I first heard of pudding stones from a KZbin rockhound, Michigan Rocks. The pudding stones he finds are usually rounded red jasper pieces in a quartz matrix and are quite beautiful. The entire stone polishes up to a high shine. Apparently these are associated with glacial deposits. I don't recall whether he finds these on the shores of Lake Michigan or Lake Huron. Thanks for an interesting talk! PS I wish I'd discovered your channel when I lived in southwest Idaho! I'm in south central Oregon now.

[@sandradankowski6120]

I subscribe to Michigan Rocks. I have a couple of pieces of pudding stone from Lake Michigan. I like the white quartz and red jasper pieces that make it a fun looking stone with a cool name. Also since it was in the lake & naturally rough tumbled, the untumbled stone is cool all by itself.

[@TreeFallFree]

Puddingstones are also found in the Lake Huron area.

[@canadiangemstones7636]

Puddingstone is a beautiful metaconglomerate that outcrops in Ontario, Canada; glaciers have taken it at least 500 km south.

[@highdesertchapteridahomast8425]

Thanks!

[@tabuleirocmd]

24:08 About this breccia core sample: I´ve seen corporate geologists classifying this as a diamictite! Very interesting your approach!

[@xcrockery8080]

Thanks, I really enjoyed this one. The other day I said something about some local rocks and my daughter (a geologist) said "duh, of course the igneous one is younger" so I am madly trying to gain more knowledge so that doesn't happen again...

[@shawnwillsey]

Yikes. Hope these help you level up your geology game with your daughter. Hang in there.

[@brucedymock6635]

Really enjoyed great revision of previous knowledge but also leant something new loved the presentation thanks 31:14

[@Rocksrock321]

Awesome video! I can now say that the samples I have found are grain supported quartz pebble conglomerates! I have found an area close to my home that has a large area of these. They are more flat than chunky and there is a creek that runs below the area where I found them . About 100 feet away. In western North Carolina. Some are quite large .

[@shawnwillsey]

Thanks for sharing!

[@joesample2176]

Great lecture once again. Love the content!!!

[@222foont]

Great class!

[@garduman]

I love your Connells t-shirt. And your videos are pretty cool too. :)

[@virgo714]

Nice classroom.. our professor says we are spoiled because we are surrounded by so much geology here in Fullerton, California

[@stevesirak]

Awesome video thank you

[@jdean1851]

Awesome info "Thanks" for posting! Shawn, can you tell where to get or how to procure a bottle of dilute HCL for geology, Happy New Year! jd

[@shawnwillsey]

Glad you enjoyed it. Obviously, I have easy access to the HCl solution through our chemistry dept. But it looks like you can get a 10% solution of HCl (which is what I use) here: www.laballey.com/products/hydrochloric-acid-solution-10?currency=USD&variant=7219003129915&gclid=Cj0KCQiA5NSdBhDfARIsALzs2ECrY9b3UT6SX94jpxe2FEtwdARFnoWQFfnd3bzUI2Y7sssI0fFZuVkaAj91EALw_wcB You would need to then get a small dropper bottle. Hope this works.

[@jdean1851]

@@shawnwillsey Thanks"

[@tinymetaltrees]

I am in the middle of slabbing buckets of glacial till. I seem to have a bit of everything. From this video: diamictite (streambed deposit?) and chert breccia. They both look very cool and I’m eager to cut them.

[@safiaamimi230]

Thank you so much!

[@CFEF44AB1399978B0011]

The conglomerate that is rounded seems like what I see in elderato canyon in Boulder. The clasts have a smooth feel to them in places like they were polished but if you place a climbing shoe on it the shoe sticks better than you might think because it still has texture. It's an interesting experience.

[@lauram9478]

❤thank you Shawn

[@MountainFisher]

I like that some of the rocks looked cut giving a better view of the "inside" structure. What do you call a car sized boulder of milky quartz sticking out of a road cut through volcanic tuff from the Mogollon or Gila Calderas Shawn? The giant quartz was translucent or I'd have thought marble.

[@sdmike1141]

Whoever came up with this rock lab content is leaning towards genius!😂. Thanks!! Helpful at any level.

[@sdmike1141]

Forgot to mention word of the day: provenance…another good one!

[@shawnwillsey]

Impressive words to make you look smart.

[@markmayer2029]

I appreciate the efforts put forth by you Shawn, thank you. I have always wondered if the Silica and Calcium cements are deposited at high, or low temperatures. Silica could be deposited at a lower temperature, under certain conditions, and Calcium at high and low (leachates). Any way to determine at what temperatures they are deposited at?

[@jethrophilippemaliao9451]

woah! thanks!

[@samratbarman9375]

Thanks

[@shawnwillsey]

Thanks!

[@pdledesma]

Neophytic question: how does silica "cement" sedimentary rocks? Specifically without being considered metamorphic?

[@music-art-theunknownsockpuppet]

I’ve been watching one of your videos. Please see attached pictures. My rock took a long time to cut with a diamond blade, really hard rock. Is my rock rare or common? Thanks! Well, it seems that I can’t include pictures in my comment

[@michaelsanfilippo7433]

Great explanations Shawn. A few questions. So I'm just a 64 year old hiker type with mostly a casual interest in geology. Here in Southern California, Coachella Valley and the Indio Hills, the material is entirely sedimentary deposits of different types. Much of it looks like the samples you showed except no breccia. However, most of the layers or bedding is very easily broken apart. Be it silt-like or sandy or conglomerate, it can be broken apart by hand or with some scraping with metal. None of the conglomerate is as solid as your samples. So am I looking at true conglomerate and true sandstone or is it better described as "unconsolidated sediment" as I see termed in my geology guides? When do I know full "lithification" has taken place? Is there no clear point going from unconsolidated to true rock? What is a good guideline to differentiate? Thanks again for your hard work producing these videos.

[@shawnwillsey]

Good question. When does sediment become consolidated enough to be classified as "rock". An age old question for sure and there's really no clear consensus. If its completely disaggregated with no cementing or consolidation, it is best called sediment (or more specifically by its grain size: gravel, sand, mud). If it holds together, even weakly, I would be comfortable calling it "rock" for the most part. Really a judgement call.

[@tomrichter9079]

Looking for a good source of chert.

[@endidasdis]

Is fault braccia in the video only polished by the faults?

[@pdledesma]

What type of rock would you classify the Connels as?

[@shawnwillsey]

jangly alternative rock?

[@mystery4004]

Hmmm! most enlightening ,

[@patrickkillilea5225]

Is the Earth is a Mega-conglomerate?

[@3xHermes]

👍

[@danknugz7605]

Hello sir. Im a gelogy student in ontario canada. The actual place where the real puddingstones came from. An area call bruce mines in ontario canada. The bruce penninsula.

[@okboomer6201]

Pudding stone is the best conglomerate.

[@happysoul8141]

😮😮😮😮😮

[@alikavyan3129]

حیف فارسی نیست

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[@shawnwillsey]

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[@shawnwillsey]

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[@shawnwillsey]

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[@shawnwillsey]

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[@seanmccaul3034]

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[@shawnwillsey]

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[@CFEF44AB1399978B0011]

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[@CFEF44AB1399978B0011]

ug, I didn’t mean for the "thanks" feature to leave a brag comment! I had no idea that was happening until I looked at the comments. :-(

[@shawnwillsey]

Thank you for your kind donation. No worries. I'm figuring it all out too. Appreciate your support and viewership.