Fluvial Depositional Environments & Stratigraphy | GEO GIRL

In this video, I go over fluvial processes, deposition, sedimentary structures, and stratigraphy, in other words, the deposition of sediment and the sediment structures that form in river environments. Deposition of sediment and the resulting sedimentary structures are dependent on flow velocity, grain size, and flow type. The two major types are braided rivers and meandering riviers. Braided streams have flows that are much wider and faster than meandering rivers, which leads to larger grain size deposition because the faster flows can carry larger grains. Meandering rivers deposit smaller grains than braided rivers, but often lead to point bar stratigraphy which contains a characteristic series of sedimentary structures that fine upward in grain size. Common sedimentary structures that form in both braided and meandering streams include cross bedding or cross stratification, graded bedding, ripple marks, and interbedding of silt and mud in the flood plains. If you play the depositional environment playlist videos in order it will make more sense. Here's the link to the playlist: • Alluvial Fan Depositio...
References: Depositional Sedimentary Environments: amzn.to/3kutTso
Facies models 4: amzn.to/3Fp5v3B
www.geol.umd.edu/~jmerck/geol...
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 fluvial environments?
0:17 Flow types and sediment transport
1:51 Flow velocity and grain size relationship
4:26 Fluvial styles (meandering vs. braided rivers)
5:53 Meandering river landforms
7:01 Meandering river deposition
8:32 point bar deposition & stratigraphy
10:02 Braided river deposition
11:17 Braided river stratigraphy
14: 02 Upcoming videos!
Hey there, Earth enthusiast! Check my favorite Earth-friendly products:
Bamboo toilet paper: shrsl.com/3cvku
Bamboo paper towels: shrsl.com/3cvkw
Compostable tableware: shrsl.com/3cvkz
Compostable trash bags: shrsl.com/3cvl0
Bamboo cutlery + straw! : shrsl.com/3cwfl
Eco-Friendly Tote (great for grocery shopping!): shrsl.com/3cwfp
Reusable straws + cleaning brushes (my fav!): shrsl.com/3cwft
Eco-friendly laundry detergent: shrsl.com/3cwgo
Directly offset your carbon footprint with Wren: www.wren.co/
(Just click link, press get started, take the free C footprint quiz, then choose how much you want to reduce your footprint by donating to the C sequestration projects they're funding!)
Non-textbook books I recommend:
Oxygen by D. Canfield: amzn.to/3gffbCL
Brief history of Earth by A. Knoll: amzn.to/3w3hC1I
Life on young planet by A. Knoll: amzn.to/2RBMpny
Some assembly required by N. Shubin: amzn.to/3w1Ezm2
Your inner fish by N. Shubin: amzn.to/3cpw3Wb
Oxygen by N. Lane: amzn.to/3z4FgwZ
Alien Oceans by K. Hand: amzn.to/3clMx1l
Life's Engines: amzn.to/3w1Nhke
Tools I use as a geologist/teacher/student:
Geology field notebook: amzn.to/3lb6dJf
Geology rock hammer: amzn.to/3DZw8MA
Geological compass: amzn.to/3hfbdLu
Geological hand lens: amzn.to/3jXysM5
Camera: amzn.to/3l6fGRT
Image sources:
miraimages.photoshelter.com/i...
geology.isu.edu/Alamo/rocks/li...
/ 525936062728903141
www.researchgate.net/figure/F...
messynessychic.files.wordpres...
www.braaschphotography.com/pag...
www.amazon.ca/Facies-Models-R...
www.slideshare.net/cwrc3/fluv...
opentextbc.ca/geology/chapter...
www.iris.edu/hq/inclass/lesso...
intheplaygroundofgiants.com/ge...
fntest213.files.wordpress.com...
uh.edu/~jbutler/physical/floo...
www.myshared.ru/slide/1105423/
www.seddepseq.co.uk/DEPOSITION...
visibleearth.nasa.gov/images/...
Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!

[@umairpioneer]

The presentation was delivered so well. It clarified certain ambiguities in my understanding of fluvial systems. I would suggest to make a video on evolution of river systems. Cheers!

[@pizzatide8328]

Legend! Saved me a lot of time with this one, speeding through the basics of braided and meandering systems. Thanks!

[@GEOGIRL]

Yay! So glad to hear the video helped you out ;)

[@henryglass8819]

Thank you, you are a really good teacher. Great work really appreciate it.

[@danielaquiroz9731]

Great and very clear presentation. Thank you!♥

[@GEOGIRL]

Thanks for the comment, I am so glad you found it helpful!

[@mgrogan2775]

Great video thank you!

[@madridi1233]

This is amazing!! Thank you

[@GEOGIRL]

Of course! I am so glad you found it helpful ;D

[@JoesFirewoodVideos]

Wednesday night boredom alleviated! I ❤️GEO GIRL

[@GEOGIRL]

Haha, having to watch old videos because I am not posting on Wednesdays? I love it! 😂👌

[@intan6409]

amazing video thank u!!!

[@GEOGIRL]

Thanks so much, I am so glad you found it helpful! :D

[@stavroullavassiliou7645]

You're amazing! 🙏🏻

[@GEOGIRL]

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

[@asedbrish-iw6zf]

Thank you

[@Get_to_the_Point]

Great vid. Don't forget helical flow, which is flow perpendicular to the general direction of flow in meandering channels. Helical flow is a large driver in sediment transport, as it is effective at churning up those sediments.

[@GEOGIRL]

Oh interesting! Thanks for sharing, I didn't know that. So helical flow would be classified as turbulent, right? Or would it be in a whole different category?

[@Get_to_the_Point]

​@@GEOGIRL Yes helical flow occurs during turbulent flow. If you watch a meander bend during flooding, you will actually see helical flow in addition to backwater flow. During flooding, backwater flow often occurs on the point bar...you will see water flowing upstream. This is one of the reasons that velocity decreases as floodwaters rise...it creates more turbulence. I think you mentioned velocity decreasing in larger flood events in the vid but I'm not sure.

[@GEOGIRL]

@@Get_to_the_Point Oh interesting! I am going to have to go watch some flood videos now! haha Thanks for sharing your knowledge, I hope many people stubble upon this comment so they can learn what I didn't know to teach them ;)

[@Get_to_the_Point]

@@GEOGIRL The true measure of intelligence is the ability to explain complex things to simple people, and they understand it. This puts you above Einstein in the IQ Dept ! Rock on !

[@GEOGIRL]

@@Get_to_the_Point oh my gosh! You are too sweet, thank you so much! ;D

[@muhammadpanezai9720]

I m student of igneous Petrology but your lectures are simply outstanding. The only problem is you speak too fast. When i slow down the speed then your voice sort of tear down further causing irritation. Plz speak little bit slow ☺️☺️

[@dangerouspoems4707]

Thank you for information

[@GEOGIRL]

Of course, I hope you found it helpful :)

[@shubhampathak6190]

Awesome Content !! LOVE FROM INDIA

[@GEOGIRL]

Thank you! ;D

[@urrywest]

I really want to know about the chemestry of pottery and concrete...

[@bharatsinghlodhi206]

Wow amazing 😎

[@GEOGIRL]

Thanks! Glad you thought so ;D

[@omeryalcnsar2391]

Pleistosendeki 4 buzul dönemi bilhassa Würm buzulu sonrası gelişmeler ilgi alanımızda...Holosendeki transgresyonun çok yönlü tetkiki devam ediyor... Saygılar sevgiler....

[@GEOGIRL]

Thanks for the suggestion! If you haven't already, I suggest you check out my Pleistocene - Holocene video: kzbin.info/www/bejne/qJS6pmSDqdushsk But if you watch that one and still want me to go more into detail on the glaciations during that time, I would be happy to, just let me know ;)

[@omeryalcnsar2391]

@@GEOGIRL Çok teşekkürler ediyorum...yarından itibaren PANGEA da Senin paylaşımlarını yayınlayacağız ...alâkan için çok teşekkürler... Saygılar sevgiler....

[@mazenomar7279]

How to recognize point bar deposits from outcrop or core data and how trough cross bedding formed in fluvial system, .thanks

[@GEOGIRL]

For a point bar sequence, I would look for a fining upward sequence with cross strat lower in the section, then ripples further up, and then interbedded mud at the top representing the floodplain. Cross bedding is just the bedding that results from migration of ripples/dunes. Trough cross bedding forms in these settings due to the increase in velocity at the inner bank of the curve, this is where the bank interferes with the flow enough to deposit ripples that migrate in a way that cuts across one another (trough cross bedding). At least that's my understanding, I hope that helps a little bit. I think you may find this video: kzbin.info/www/bejne/nJ60iXqKZ9SIpNE helpful (it's my sedimentary structures video where I talk more about these structures & depositional environments). :)

[@mazenomar7279]

@@GEOGIRL many thanks for your quick responce.

[@GEOGIRL]

@@mazenomar7279 Of course ;)

[@multi.tasking]

How can we recognize the old from the recent deposit? Does the fluvial system respect the stratigraphy principle?

[@GEOGIRL]

Well if you mean recent as in modern, then there would still be a river there... Whereas, an ancient stratigraphic section indicative of an ancient fluvial system would not have a river there and would contain consolidated, compacted, & lithified sediment rather than unconsolidated sediment. If you mean recent as in ancient, but relatively young compared to another outcrop, then you would have to find a way to date the strata in each outcrop to compare them. Unfortunately, sedimentary materials are not easily dated unless they contain fossils indicative of a certain time period (index fossils) or strata that is volcanic in origin (e.g., volcanic ash) which can be dated using isotopes. So it depends... But the good news is, in ancient strata, there are typically layers either above or below the un-date-able layers that will give ages with which you can constrain the age of your middle strata if that makes sense. Regarding your second question, I am not aware of a single principle of stratigraphy, but I do know of the principles like Steno's laws (superposition, original horizontality, lateral continuity, etc.). If you are referring to those principles, then yes, fluvial systems obey those. Hope that helps ;)

[@sppu6609]

Geo Girl you beauty ..

[@aminecherif289]

Good presentation, I am currently following your videos, hope collobartion with you, best wishes from Ouargla university, Algeria

[@mohamedashrafelsherif6458]

please please please speak slowly

[@GEOGIRL]

Thanks for the suggestion, I know I was really bad about this for a while, I hope i've gotten a bit better in my more recent videos haha

[@mohamedashrafelsherif6458]

Your videos are amazing