What is Clay & Where / How Clay Forms | GEO GIRL

[@GEOGIRL]

CLAY DEFINITION CLARIFICATION: I tried to get this across in the video, but I've been seeing many comments that indicate I didn't do a great job, so I just wanted to say here that CLAY IS BOTH A SIZE AND A COMPOSITION! I state at the beginning of the video that it is defined by size, but if you KEEP watching, I then go on to discuss the fact that only certain compositions of material exist at that size, and these are secondary, layered aluminosilicates, which are what geologists define as 'clay minerals'. However, there are also oxides that can sometimes be clay-sized and are sometimes called pelagic clays becuase they form on the seafloor (in the pelagic zone), but they are not considered 'clay minerals' because they are not aluminosiliates. Why do we make this distinction? Because aluminosilicates have a very specific platy structure and this causes them to behave differently than materials that aren't platy (like certain oxides). But don't worry, I talk ALL about clay structures in the follow up video to this one! ;) Also, I see lots of angry comments because I used fractions & metric, so I just want to say I only did that because the reference I was using did that and I thought it was hilarious haha! So please don't be mad at me, I would never do that for real, but the point here is the actual value doesn't matter, it is just VERY small lol ;) Lastly, I had a typo in the end-screen. Pretend it says Mineralogy Playlist rather than Planetary Science Playlist ;) Thanks! haha

[@davidniemi6553]

You also used "loose" for "lose" about 60% of the way through, of course you pronounced it right.

[@GEOGIRL]

@@davidniemi6553 Haha oops, good catch, at least the point still came across! ;)

[@Stupidityindex]

I play around with a tractor on a small farm & I noticed patches of extremely sticky natural clay. I wonder how it is formed.

[@tubester4567]

Excellent information I learned a lot. I bet you could choose the best clay to make bricks!!!, I always wanted to make my own bricks. Not to mention you know where the gold, silver, copper, iron, etc is hiding.

[@d.t.4523]

You had the camera pointed in the right direction, that has to count for something!

[@Hellbender8574]

Good idea to do a soil science series. Dirt is way cooler than it gets credit for. My son found the orange iron oxide clay layer beneath our garden and figured out how to make little bricks dried in the sun. They're surprisingly hard and sturdy so he built a little border out of them.

[@GEOGIRL]

Wow what a bright kid! Who needs TV when there's clay outside! That's awesome ;D

[@geraldfrost4710]

Has he tried firing them? Takes more than a kitchen oven. Perhaps a local school or craftsman? Most teachers and artisans melt to hear honest curiosity. Good luck!

[@TheJamesRedwood]

Soil and dirt are not the same concept. Soil has organic material in it, and is made of structures of clay, silt and sand, created by that organic material, called aggregates. The meaning of dirt is fully associated with being unclean, not the source and recycling system of all life.

[@TheJamesRedwood]

@@SirAlanClive Thank you for the compliment. This is an educational channel after all, so accuracy and etymology are important. I liked out host's definition of dirt as being "soil displaced". I do not know if this comes from a scientific definition but it is a poetic interpretation.

[@TheFarmacySeedsNetwork]

@@geraldfrost4710 See a channel called primitive technology... guy builds everything using primitive tools... makes his own bricks and pots.. fired with wood... and buildings too... and even harvests iron ore and creates metal stuff with it. Very cool channel! cheers! here's his latest video: kzbin.info/www/bejne/faLLqZiVpbFpjdU

[@user-nz6ug4ru8f]

The basics of clays has never been explained to me like this. You make it sound so logical and understandable. Thx.

[@GEOGIRL]

So glad to hear that :D Thank you!

[@andywomack3414]

In order to field test for clay, one must have a taste for knowledge.

[@GEOGIRL]

Hahaha exactly! ;)

[@andywomack3414]

@@GEOGIRL I wish I could claim originality with that, but I saw that with accompanying photo in a geology text many years ago. I would attribute if I could remember where In saw it. I have had some summer work testing the engineering properties of soils, and a little clay can go a long way as far as affecting those properties. Where I worked had problems with expansive clay made up of bentonite.

[@KerriEverlasting]

@@andywomack3414 naaaw that's such an honest admission! You can claim it by virtue of time by now surely lol

[@erikjohnson9223]

And no fear of contamination by urban or agricultural pollutants. Or squirrel poop.

[@jd83241]

I knew an adam womack in fort worth Texas any relation?

[@keithlightminder3005]

Getting into “wild clay” which involves prospecting useful ingredients of clay bodies for pottery, building and maintaining good relationships with the people plants and critters of that land, and lots of experimenting to make clay bodies and glazes. This is golden! Thank you! So glad to have found this channel. Learning so much.

[@christiancarson7566]

I just discovered this channel 2 weeks ago and I love it. I need to check out your video on soil. By the way, I grew up on a farm on the Valparaiso moraine in Northwest Indiana. Due to glaciation moraine soils are all mixed up. It is possible to have multiple soil types in one small field. Yeah I'm weird, I love dirt, or more accurately soil.

[@peterladan5208]

Thank you for a fantastic video again! We are making the finishing touches to our geopark in the middle of Sweden that will be opened in June next year. Two weeks ago we were put on the IUGS list of the first 100 geological heritage sites in the world. It is fantastic to see you present all the topics that are represented in our park. I wish you lived a little closer so that we could have you here with us to get people enthusiastic about earth science. Looking forward to your next video!

[@indigoblue4791]

Congratulations a brand new Geopark for Sweden is fantastic for the people there. 😊✨

[@sayagarapan1686]

This compelled me to finally look up what pottery clay consists of and how it's classified. There's a lot I don't know but have always wondered at. Totally playing catch up here. The soil at my dad's house in Illinois is heavy with clay and I've always wondered at it's origin and how it is classified as clay verses silt, soil, & sand. I was born and raised in the Pacific being a half island boy so U.S. geology was never really a prominent interest for me until now. I heard tell that everything East of the Mississippi River is buried under several feet of eroded Appalachian mountains where it hasn't been scraped to bedrock by glaciers, forcing me to wonder how big those mountains really got and where it all went. All very intriguing, and for me, a mystery to uncover. Sand and lava has been my forte`. Cuts your feet and gets up in your shorts so it has a way of remaining imminent.

[@SeaScienceFilmLabs]

To the Sea, My friend…

[@AnnoyingNewslettersPage6]

to the open arms of the se-a

[@alexander.Rainforest1987]

And all those sandy beaches in the coastal plain and Florida beaches. The Appalachian mountains were as high as the Alps, or higher during their uplift.

[@jasonreed7522]

@@alexander.Rainforest1987 the Appalachians at their peak were on par or greater than the current Himalayas. They are also older than bones which is so weird to think about.

[@georgefspicka5483]

Wow! What a flood of facts … I love it! I’m basically clueless about soils, which is why this presentation is so cool to me. Most of what I learned about clay in the 80s, had to do with deposition in deltas and such. Adios Amigo :)

[@LuisAldamiz]

This was the geology lesson that my formation as gardener was missing. Bookmarking it. Thanks.

[@claywyatt1982]

I've been discouraged a lot lately and searching for direction in my life. This video is quite helpful! Thank you!

[@conchobharkhan4167]

“Did you chew it?” Is a sentence that every geologist has heard from a person that is 100% serious

[@gaufrid1956]

Now I know why the soil here in Cagayan de Oro City Mindanao Philippines is red, and so is the soil in the tropical north of Australia! Also "Down in the west Texas town of El Paso, there lives an amazing Geo Girl"!

[@KerriEverlasting]

Omg I got my "Ask me about geology" cap! Woo hoo! It's so nice! I love it so much! 😍

[@cybersandoval]

thank you for the little clarification on soil versus dirt, nice

[@Mjr._Kong]

Came for the cute thumbnail, stayed for the excellent discussion. You have a natural gift for sharing (potentially dry) information with enough charisma to make it palatable -- even interesting! Earned a sub.

[@firbolg]

I hated geology in school... mostly my teacher's fault since she couldn't have made her classes any more academically boring. But you, I can watch you all day!

[@GEOGIRL]

I agree, the teachers have always been the ones that either make or break a class for me. I am glad you find my lectures interesting despite your precious experience though! :)

[@davidniemi6553]

Fascinating and informative. I live where there is an above-average amount of rain year-round, the soil is acidic (pH 5.5 - 6.0), and mostly heavy orange clay with rocks mixed in. Not ideal for growing useful plants but manageable.

[@davidniemi6553]

@@TheBirdBrothers No, northern Virginia, which is consistently pretty wet year-round, and wetter than a number of places people think of as rainy.

[@alanbelasco2931]

Awesome! I watched this video a year ago and didn’t get much of it. Since then, I’ve spent a year studying geology and I did a field study of a local conservation area which forced me to learn a lot about minerals, in particular aluminosilicates. So, when I watched your video today, I get it. Thank you!

[@jadams3427]

You nutty geologist ! Actually I remember this grain size stuff from schooldays. That was over 5 years ago now, as I am now 64. Thanks for the interesting video !

[@oker59]

I remember being struck by how corrosion, which I spent way to much time fighting in the Navy was an electrical circuit phenomenon. I can't help noting that while watching this geology topic involve ions below the surface, and making soils!

[@ukaszbadura5670]

I am a geocacher and from time to time I look for so called Earthcaches and currently am working on creating Earthcaches myself. Your videos are really a great resource. Thanks!

[@Ariccio123]

What's an earthcache

[@1a1u0g9t4s2u]

Thank you for an in-depth discussion on clay. So glad I came upon this video as I wondered about native clay I find while out off roading or hiking versus the clay purchased in pottery stores. Thanks for sharing.

[@bucc5207]

"Clay is a size" and soil versus dirt so feeds my inner pedant. Thank you!

[@myth-termoth1621]

As a science nerd and potter i cannot wait for more videos in this series. I would like to know more about the clays formed from various types of basalt since i live on the edge of a volcano which erupted some andesite and later a more maffic dark coloured basalt, and i use clays deposited locally from the erosion of the volcano.

[@camelopardalus]

Not many people have the gift to make dirt sound so fascinating.

[@GEOGIRL]

Ahh yay! This makes me happy! ;D Dirt is AWESOME!

[@triedzidono]

@@GEOGIRL always a very telling thing, the type of dirty jokes that amuse people. Soil making you laugh, because its in bags, I doubt i will visit a garden center again without that joke repeating in my head. & i like that.

[@alanfarrance8639]

Bloody hell Geo Girl, you packed a lot in to that video! There’s a lot of good information that I’d wondered about though not understood before. Thank you.

[@OzGeologyOfficial]

Well done. You explained this well. It's a surprisingly complicated topic even though it's just clay lol. Especially when you get into different forms of it, like Kaolinite.

[@trindal359]

Five star presentation, just fantastic and all the slides can be read on a fone screen, thank you. So when clay is fired in a kiln, it always changes color, and some is better than others. There is really pretty stoneware from asia that is a deep chocolate brown

[@pukulu]

I remember learning that Montmorillonite and Kaolinite formed at or close to the surface primarily as a result of the weathering of feldspar, mica and amphibole in the presence of water, wind and temperature fluctuations. I've hiked in the hills in Southern California and have seen the weathering process up close. Cliffs made up primarily of feldspar start deteriorating and flaking off and a soft, dirt-like substance replaces them.

[@GEOGIRL]

Absolutely! I discuss monmorillonite and kaolinite in detail in the next video on clays (clay composition and structure), I can't wait for that one I am a sucker for geochemistry :D But in any case, you are absolutely right those phases form from feldspars, micas, and amphiboles. Have you ever seen when a rock has been weathered in a way that it looks like an onion peeling, those are my favorite! -> see pic of what I mean: media.istockphoto.com/photos/rock-macro-onion-skin-weathering-weathered-stone-texture-picture-id502456826?k=6&m=502456826&s=170667a&w=0&h=l5F_vvgTbXTs9nQ98OiUpS__B9LBxgYG-p9a_QDPEQU=

[@pukulu]

@@GEOGIRL I love geology in my old age. I studied mathematics when I was a young man, but had a broad education in the sciences - chemistry, physics, astronomy, biology, zoology, genetics, botany, etc. I must say that I appreciate the work that you do in preparing these videos and the pleasant manner in which you present them.

[@traildude7538]

@@GEOGIRL I picked one of those up once -- or I should say I picked most of it up; the outer layers spalled off the moment I grabbed it.

[@daleheldberg6568]

Great video, thank you. So glad I found your KZbin site

[@KerriEverlasting]

Omg Monday morning getting ready for work!! I'll be looking forward to this when I finish! Thank you sooooo so so much!! You are amazing! 💖😍

[@bentonjackson8698]

I'm an amateur geologist that has picked up pottery as a new hobby in the last few months. I'm very interested to see where this series goes! I'd like to see some discussion of how different clay types are used in pottery.

[@charleslambert3368]

Have you seen Atomic Shrimp's recent videos? He cooked stew in pots he made from local clay dug out of the ground during building work at his friend's house.

[@bentonjackson8698]

@@charleslambert3368 No I haven't. I have pottery-grade soil in my yard, I dug out a chunk and made a couple pots out of it. I don't have a kiln though, and the studio where I'm taking classes won't fire wild clay.

[@Coastal0]

Great summary of clays!

[@lubricatedgoat]

Clay might be the most important substance there is: I've read that it could have catalyzed the early chemistry of life itself. It also served as a very important tool for recording the first writing, and then there's its use for holding water/liquids and food. Almost forgot to mention its use in construction. Like I speculated, it may be the most important substance, at least to mankind.

[@majorlycunningham5439]

Indeed. Anthropologists and archaeologists have discovered clay pottery shards in almost every known habitat of ancient civilization. As one of the pre-historic techs, it was one of the first materials that could be manipulated to serve multiple uses. Artisans still make beautifully crafted pottery to this day!

[@Margoth195]

I respectfully disagree. I would argue water is much more important especially for life chemistry. The fact that fluid chemistry is much faster and easier to control than solid state or gasious chemistry (respectively) and water is one of the few substances liquid over such a large relative temperature makes it much more vital (not to mention it's polar nature and ability to be protonated and/or deprotonated). I will grant you the mastery of clay is a hallmark of many civilization but there are no civilizations that have existed without water. Regardless, I'd be interested to see the source that claims clay's importance in life chemistry.

[@lettybastien4624]

Oxygen for the Win!

[@lubricatedgoat]

@@Margoth195 Definitely water is an absolute given, and maybe the most important molecule we know of related to our version of life. It'll be interesting to see what life we may be able to simulate and constrain in other solvents such as liquid CH4. Just punch in something like 'Organic synthesis clay catalysts,' and I'm sure you'll find tons of info. There's even new research into types of catalysts involving kinetic energy over direct chemical reactions (think firing molecules at a wall with shapes on it that cleave or form bonds). We're still noobs. Much to learn.

[@lubricatedgoat]

@@lettybastien4624 Life evolved on Earth way before it needed oxygen, but I'm sure glad it made the switch, allowing energetic creatures like us to contemplate such.

[@justme7415]

I've been doing a dive into geology vids lately and was just asking myself wtf clay/dirt/soil is. Then found your vid. Thank you!

[@RulgertGhostalker]

that rocked !!! i learned so much because i didn't know about any of this ... i need to de-specialize more anyway. i need to learn more about the why of soil acidity, and the why of poor or excessive drainage....i knew that, but i didn't know what i needed to know before.

[@spindoctor6385]

We should all take a second to appreciate Geo girl's subscriber engagement. She has replied to nearly every comment older than two hours. When this channel has 1 million subs it will become impossible, we are a privelidged group.

[@GEOGIRL]

Aw you are so sweet to notice! I am trying to keep up, every morning I try and go in and respond to all the new ones but it is becoming slightly more difficult hahaha! Hopefully I can keep this up a bit longer ;)

[@lwentz5510]

Well done! Quite interesting. I'll never view that bag of potting "soil" the same way again. Example, "You are dirt, do you hear me, you bag of soil!!"

[@TheOtherGuybo]

This is fantastic. Soil is so fascinating. Who knew about clay!

[@ketonshaw4809]

Yesterday I bought my mother a pottery wheel for Christmas, clay must be on our minds. Lol. Thank you for the post. love the videos. Ps. The sound on your videos sound much better.

[@GEOGIRL]

Oh how nice! Now you can tell her all about clay minerals when you give it to her! haha ;)

[@gingazaurus]

Very interesting and well delivered video. Thank you for sharing.

[@mondkalb9813]

Thas was very interesting. :) I played a lot of Dwarf Fortress and learned a ton of new words (lots of names for stones and soil material) whithout really knowing what they ment. You probably don't know the game, but soil, minerals, stone, and metals play a huge role in it (of course, it is a game about dwarves ;-)). The game world is procedural generated with accurate geology, climate, biomes and so on. Soil layers with sand, loam, silt, and clay are nice to have in the game for growing plants and making glass and pottery. It is nice to have a better understanding of these materials now. It never occured to me, that they are basicallly the same material only with different grain sizes.

[@dementiasorrow]

I've watched a few of your videos and I liked them a lot, but this series on clay is my jam. I'm now a subscriber. You're very good at explaining things! thanks!!

[@myamazingjack8366]

Great topic, love earth science. Years ago I watched a 48 lecture Great Course called "How the Earth Works" and thought it was great, and have been looking for a more in depth follow up since. Your channel fits the bill nicely. And your presentation is fabulous, at least from my perspective.

[@triedzidono]

totally unfluffy & straight to some serious facts. (new subscriber)

[@GEOGIRL]

Thank you! Glad you like my to the point lecture style ;)

[@BenjiShock]

This is awesome! I really hated the fact that we learned about all of these horizons in school but they were kind of mysterious to me because we never learned what kind of material these horizons are actually made of! I get that it can be kind of overwhelming, but you don't need to remember all of the different molecules and they are mostly variations of silicate anyways so its really not that complicated.

[@fiegenfiegen]

THANK YOU! All of a sudden, I understand why all the roads in rainy parts of Africa is so very red!

[@RichardSmith-ms6hh]

Appreciated. I live near the St Austell (Cornwall, UK) china-clay (kaolin) area. No prior knowledge of geology, but am scientist. Your presentation worked great for me. Thanks.

[@rogerdudra178]

Greetings from the BIG SKY. Paddlefishing in bentonite clay is a learning lesson.

[@stavroullavassiliou7645]

Love your work! Thank you 💕☺️

[@GEOGIRL]

Thank you so much! So glad you enjoy my videos ;D

[@TheReubenShow]

A lot of clay here in Phoenix, I managed to make pottery from the sticky mud in the yard. I mixed the soil in water, let it settle, then poured out the water, and the clay settled from that.

[@hhiippiittyy]

I'm in southern New Brunswick, Canada, and there is some nice clay in the creek valley down the road. I got my first small field gathered batch completed this summer. From what I've read, it will do well to season it. I'll try working it after a year. I look forward to gathering more substantial amounts next summer. I'd like to have a good bank of clay by the time my garden is set well enough to afford me the time to make a little kiln.

[@jeremycrochtiere6317]

Thanks for the information, And the adorable demeanor making geology interesting, and a little amusing.

[@Get_to_the_Point]

Alas, I finally understand where clay comes from. Thank you !

[@AnnoyingNewslettersPage6]

Pre-roll ad for Seattle Pottery kilns. Perfect pairing 😅

[@GEOGIRL]

Haha oh that's so funny!

[@nexusone5955]

It's kinda nutty how much of this made perfect sense because I've played Dwarf Fortress.

[@stephenelberfeld8175]

In Vermont, the glaciers left behind clay concretions and sand concretions. They are usually rounded or formed into smooth irregular shapes. In Putney/Dummerston,VT near the Rt. 91 turnoff fron Rt 5, the clay concretions are sometimes bicolored compound shapes of brown and grey. In Plainfield, VT there is a sand pit where the concretions are up to a foot in diameter, and you would need to scrub behind your ears after collecting there.

[@realcourte]

To clay or not to clay? That is the question! 😅🤣 Awesome vid again!

[@scottfw7169]

This brings to mind driving in the rain on wet red clay roads in the 1970s in Georgia (the US state not the European country) and there was a certain point of saturation where you might as well be driving on marbles in oil. Mind's eye can also recall dry days where the roadside plants were all covered with red clay dust.

[@curiodyssey3867]

Ur laugh is so genuine its contagious

[@xINVISIGOTHx]

would it be impossible to make a "clay" pot out of silt, like if you were in the wilderness and you made a kiln and all you have is silt?

[@alexander.Rainforest1987]

Clear and concise, thanks.

[@christianhunt7382]

This is the excuse I've been looking for to satisfy my neighbors curiosity. Thanks GeoGirl!

[@GEOGIRL]

Haha you are so very welcome! ;D

[@feiter]

Thank you!!! I've been looking for a video on this exact topic for years

[@GEOGIRL]

You're welcome! So glad you found this and enjoyed it ;D

[@darrenhay5672]

Another great vid! The more I watch, the smarter I feel....even if I am now tempted to taste test for grain size!

[@GEOGIRL]

You gotta try it at least once ;)

[@janewray-mccann2133]

Great stuff young geo gal, a fairdinkum benchmark chronological presentation of the sedimentary origin of one of my own favorite regolith topics, the origin of clay. Well done to you, you rock. Regards Rory, Tasmania..

[@footfault1941]

It's all about clay, nothing but clay. Very interesting bits unusually. Apart from a normal treatment of geology or paleontology, this is another version with a singular touch. The presenter herself is visibly enjoying the subject (sprinkled laughter is an unequivocal evidence). Very informative & illustrative. No wonder clay is in high demand among elephants or macaws. Size matters. From the very beginning, viewers' attention is firmly caught. She's a knack or two. Clay, sand, & silt ... Looked like a cocking video. Special thanks for geologist's private secret!

[@traildude7538]

I do conservation work in dunes. One of the things I do is to water heavily with water that has about as much suspended clay in particles as I can. People call me crazy, but those tiny particles get down in between the sand grains and increase the ability to hold water immensely.

[@kevinkuszniryk7777]

This is great. Thank you and best wishes.

[@GEOGIRL]

Thank you so much! ;D

[@spaceinyourface]

Another great video,,very deep,,,way over my head,,,I see why physics is one of the easiest scientists to study. I worked with clay at the Wedgwood factory for 8 years ,,in the slip House,, I thought that we probably used more clay than any one else but I found out the ceramics industry is just a small user,,,,glossy paper uses a lot more. My finger nails were allways shiny.

[@GEOGIRL]

It's so funny you say that because I study biogeochemistry but still think that physics is SO HARD! hahaha

[@barbaradurfee645]

Interesting, I need to research glossy paper manufacturing now 😊

[@spaceinyourface]

@@barbaradurfee645 yea,,It's one of the reasons glossy paper won't burn to well.

[@johnqueen2754]

I'm in the mountains of north Carolina. we have the lovely gray clay, used in pottery making. B. B. Craig made pottery around here for along time.

[@loquidity4973]

Awesome video, awesome teacher/professor! Thanks!

[@oldionus]

What a great lecture.

[@GEOGIRL]

Thank you! :)

[@kevinrussell1144]

This is well done, kid. You've kept the discussion at a comprehensible level without talking down to your audience. I'm sure you'll say somewhere that there is a distinction between clay-size particles (that may or may not be clay) and true clay minerals. A mud formed of mostly silt-size quartz grains would be very diferrent from one of mixed fine sand, silt and clay-sized particles of heterogenous composition. And most of the "soils" we work with out west are formed from transported alluvium and are not (typically) derived in place from bedrock. California's Central Valley soils are mostly sourced from erosion of the ancestral Sierras and are fertile because of mixed rock type sources and the climate is so cooperative with warmth/hot weather and long growing seasons.

[@patkelley8293]

I'm going to give this channel a shot. Had a rock collection as a kid (that some idiot sold) but I'll hang out. Super wonky but I'll just have to pay attention. Great presentation!

[@randallwehler1186]

Very informative video as I am a resident of Clay County (city of Moorhead) in Minnesota at the southern end of what was Glacial Lake Agasizz.

[@mosquitobight]

Southern Manitoba here. That clay is the bane of homeowners due to spring flooding and foundation shifting. It also creates the swampy conditions that are the perfect breeding ground for my namesake.

[@majorlycunningham5439]

This is really useful to know. If you’re ever curious about early construction tech, clay as a material has been used ubiquitously throughout the world due to its ready availability. It’s pre-fired pliable form can be used to make almost any shape, which meant it was used heavily before more advanced materials like bronze or steel and later plastic. 🤓

[@Ironfootball69]

Very nice...💖 excellent video... very well done geo girl...✨✨✨

[@GEOGIRL]

Thank you ;)

[@Ironfootball69]

@@GEOGIRL most welcome 🙃🙃✨✨

[@TheNativeTwo]

Nothing more beautiful than a woman who knows her science! Thanks this was illuminating. Question: how do the composition of clay/silt/sand change the soil PH? Does the PH of the clay depend on the mineral that the clay is made from (from weathering)?

[@holyworrier]

My pottery class took a trip to a cave in north central Arkansas. A few hundred yards into the cave was a chamber in which one wall was solid red clay. We took samples and moulded little pots on the spot. The teacher explained that the clay was too plastic in it’s pure state, but could be blended with gray pottery clay to create objects. It was so fine that anything made with it would crack as it dried. It is presumed that Native Americans used it long ago in just such a blend with coarser clay. I wondered if clay will ferment over the ages, because this clay had such a pungent odor.

[@stevedrane2364]

Brilliant. . Thank you . . 👍

[@macgonzo]

Great video! Thank you for making this 😊 I don't know if you'd be interested in making a video about this, but I thought I'd ask... Here in Scotland, we have archaeological structures called "vitrified forts", which are iron age and early mediaeval hill forts in which the stones of the walls have partially melted, forming glassy conglomerations. It is believed that these were created deliberately by the Picts (the native people of Scotland at the time), but experimental archaeology has failed, time and time again, to replicate what we see on the ground. I was hoping you could make a video about what physical conditions are needed to cause this vitrification, and I would be incredibly appreciative if you could consider whether any natural processes could cause this - specifically large-scale forest fires, leading to firestorm conditions, which is what I believe is the most likely explanation for these vitrification events. Thank you for considering this, even if you choose not to pursue this.

[@GEOGIRL]

Wow, that is so cool! I have a feeling that if experimental archaeology has failed to replicate and explain the process then I'll probably have a hard time doing so haha, but I will look into it and give it a shot! Thanks for the suggestion ;)

[@macgonzo]

@@GEOGIRL Thank you for considering this - these forts are something most people haven't heard of, even here in Scotland - so please don't feel any need to justify not doing a video on this, I have no expectations. That said, the issue with the experimental archaeology was that the hot air rising from the fire would draw air inside the wall, thereby cooling the internal stones, which meant that it was impossible to generate the required heat. Because of this, the only way the Picts could have generated the required temperatures would have been to build structures, such as turf walls, surrounding the fort to trap the heat... I just don't see them going to that much effort, to gather tons and tons of turf, carry them from miles around up to the top of a hill, then build a wall around these forts, just to melt a bunch of stones... Especially when the evidence shows that a number of these forts were reused after the walls melted... It just seems implausible to me... My view is that if there was a massive forest fire, this would provide a natural explanation for what we see, but I don't have the scientific chops to be able to prove it myself 😢

[@martingisser273]

Fascinating! Perhaps the forts were initially used as lime or pottery kilns? After so much effort to erect them, why not do something productive first? To test this hypothesis I would look for remains of underground aeration shafts.

[@martingisser273]

It is unsurprising that experimental archaeologists couldn't yet reproduce it: The art of fire is lost.

[@ernie5229]

I love how they use fractions on millimeters!

[@indigoblue4791]

I am so excited to find your video!! I love your channels content. I might be a bit of a 🤓 nerd but that's good with me! Subscribed! 😊🌟✨

[@GEOGIRL]

Thanks so much for the comment and for subscribing! I am so glad you love my channel :D

[@victoriaburkhardt9974]

Thank you.

[@noahdull6950]

So amazing!

[@mercurywoodrose]

when i travelled in italy, i was on a bus to the city of Siena. i noticed that on the side of the road, in stark contrast to the bright green grass and crops, the disturbed soil along the road was a brilliant orangish brown color. im just so convince that that was the pigment known as SIENNA, and that its origin is in that regions clay deposits. now i could look it up, but i made this observation in 1994, prior to the internet, and have just lived with it since. makes me feel good. i used that crayola crayon color all through my childhood, both raw and burnt sienna.

[@billkallas1762]

I always thought the soils had much more than 4% organic material. I was thinking 10 to 15%, for topsoil, unless it was just landscape material.......Oh well. I live in an area that is covered in soils brought down from Canada by the Glaciers.

[@GEOGIRL]

Well I think it definitely varies, that's a great point! There are regions where the organic layer (the O horizon) is MUCH thicker! And then there are regions where it's much thinner, like where I live in the desert ;) Edit: I should mention too, I think (because the organic layer is the top layer), this percentage would depend heavily on how deep you go when determining relative percent of each of these components. I think this 4% estimate was made going all the way down to the bedrock below all the soil layers (way passed the top soil), so it is a pretty high percentage considering soils can go extremely deep (~50+ ft or 15+ m deep).

[@willo7734]

Cool, I never would have thought I would be interested in a video about silt and clay but you are engaging as always. In the American South where I’m from there are people who actually seek out clay to eat. I understand that white clay is a particularly prized delicacy though I’ve never partaken myself. Good to know that this practice was condoned by an actual scientist 😂.

[@GEOGIRL]

Hahaha Yes, go for it! 😂😂

[@geraldfrost4710]

There are some bad chemicals in SOME clays. Most of the chemistry is benign, and passes straight through. Some of the chemicals are needed by our bodies; because of the small size (better absorption) they are used in dietary supplements. Like eating mushrooms in the wild: (insert metaphor here).

[@traildude7538]

Actually there's a good chance you've eaten clay if you've ever had a really creamy rich milkshake, at least according to one of my university geology professors: he asserted that many fast-food restaurants add Bentonite clay to make milkshakes thicker and creamier.

[@sophierobinson2738]

The people who crave and eat clay are generally suffering from Pica, and eating the clay just makes the condition worse. It is a form of anemia.

[@johngrundowski3632]

Great topic , this is essential to locating plants/ gardens. Thanks ♒

[@GroberWeisenstein]

always wanted the dirt on clay. good video.

[@GEOGIRL]

Thanks! ;)

[@geOCognition]

Thanks for the interesting soil intro. Just one cue in addition: DIRT is defined as Soil in a wrong place 🤭...

[@1voluntaryist]

In the 50's I experimented with my heavily clay soil. It tested, using the water/jar method, as 40% clay, 40% silt 20% sand. I screened, then added a liquid mix of 50/50 water/emulsified asphalt, available for $5/55 gallon. I poured the mix into molds 1'x1'x6". They were dried in the 100+ sun, then used as in a pathway around the backyard garden. They were still about the same 40 years later, only slightly worn. Note: No cement was necessary for this adobe block.

[@theobserver9131]

SWEET! I've been wanting to know this for many years! I am pretty busy with life, so I keep forgetting to look it up, and you just brought it to me in fine detail! Thank you so much! One of my possible future occupations is as a potter. And or sculptor. I am living in an area that is rich in red clay, and I play with it a bit, filtering out, or settling out everything that is not clay by making a wet slurry, and let it settle into layers. I look forward to your follow up video! I'm going to look through your collection and see if you have made it already. Obviously, I have subscribed, and given you a thumbs up!

[@theobserver9131]

Don't worry, I am interested in more than just clay. I will stick with you to learn more about our wonderful planet!

[@theobserver9131]

I see to the right a video about eukaryotes. I am about to devour that one!

[@Margoth195]

thanks this was informative.

[@TheFarmacySeedsNetwork]

Thanks so much! This is excellent info! subbed! Tip number 1: Eat rocks and see if they are clay 😁 Organic matter (humic matter) is about 38-42% lipophyllic acid aka fat Microbes that eat rock interact directly with plants and actually mine rocks in the soil at the plan'ts direction through the use of microbial metabolites that the plant produces as exudates. For those who don't know, clay soils are some of the best growing soils due to their high nutrient content locked up in clay colloids. Microbes are excellent at releasing these.

[@neilwatson9368]

Well done. I took a smidge of soils in the early 80’s. By gosh or by golly, I ultimately made a decent living from all that knowledge. Why, Because I oddly, retained much of it and had very little competition. A diligent bloke, could watch this video 15 times and easily pursue a lucrative agricultural career.

[@rickemmet1104]

Hey Rachel, whodathunk I'd spend 18 minutes listening to your review of MUD? LOL! This is really interesting though and it pertains to a couple of things that are of interest, one is building with Rammed Earth and the other is Permaculture. With RE, you want to avoid some clays (though others are of great benefit) and with Permaculture the type of soil you have will greatly effect the types of plants you can grow. Looking forward to your next installment :)

[@surrealness]

THANK YOU GEO GURL

[@jakeshuster6783]

I love clay. we have been packing in clay to our bike jumps for years. just gotta cover it for erosion.