Shoreface Depositional Environments & Stratigraphy | GEO GIRL
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- čas přidán 5. 07. 2024
- Ever wonder why beach sand is so well sorted and beautiful? Shoreface depositional environments are the regions of the beach and the near-shore region of the continental shelf where beach sand is deposited, weathered, rounded, and sorted. In this video, I go over shoreface, or shoreline, depositional systems, including wave and current processes, the zones of the shoreface (upper, middle, and lower), and the sedimentary structures and stratigraphy in each of these zones. Over geologic time, the movement of the sand along the beach and shoreface environments leads to sedimentary structures, such as trough cross bedding, hummocky and swaley stratification, ripple marks, and laminations, but these structures form in different regions of the shoreface environment. The upper shorface, middle shoreface, and lower shoreface lead to distinct sedimentary structure sequences due to the difference in the wave strength that hits the seafloor at each depth. What does wave strength at the seafloor mean? Well waves have a base, the rotation of the water molecules in waves becomes less strong with depth and ends at a certain depth, this is the wave base. The wave base is deeper during storms because the stronger winds form larger waves. For this reason, stratified layers of rock form in the deeper parts of the shoreface during storms than they normally would. I also go over how to recognize these shoreface environments in the rock record and certain trace fossils that will help you distinguish which zone of the shoreface you are looking at. Hope you enjoy the video! ;)
References:
Depositional Sedimentary Environments: amzn.to/3kutTso
Facies models 4: amzn.to/3Fp5v3B
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/where are shoreline environments?
0:14 Wave processes (how waves work)
2:33 Currents (currents are different than waves!)
3:22 Shoreface environmental facies
4:39 Shoreface deposition & stratigraphy
5:26 Beach/foreshore stratigraphy
5:41 Breaker zone/upper shoreface stratigraphy
5:50 Lower shoreface stratigraphy
6:38 Ripples, & hummocky vs. trough cross stratification
8:25 transgressive vs. regressive sequences
10:40 Ichnofacies (trace fossils) in shoreface environments
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Non-textbook books I recommend:
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Alien Oceans by K. Hand: amzn.to/3clMx1l
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Image sources:
www.greecetravel.com/thessalo...
geology.isu.edu/Alamo/rocks/li...
web.arc.losrios.edu/~borougt/S...
sepmstrata.org/page.aspx?pagei...
www.geocaching.com/geocache/G...
www.amazon.ca/Facies-Models-R...
www.flickr.com/photos/1358217...
www.geocaching.com/geocache/G...
/ 157485318203242721
geologypics.com/hummocky-cros...
basdargeophysics.wordpress.co...
commons.wikimedia.org/wiki/Fi...
geologylearn.blogspot.com/201...
speedstar71.blogspot.com/2014/12/
www.geol.umd.edu/~jmerck/geol...
www.schursastrophotography.com...
www.geol.umd.edu/~tholtz/G331...
www.hayesandjarvis.co.uk/holi...
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! - Věda a technologie
I'm from Taiwan and my geology professor loves your channel and promotes it to us! We even have a homework about your videos. Although we complain about more homework, I still love your videos
Wow, this made my day! I am so glad your professor thinks so highly of my channel to assign homework to you! I apologize for the extra homework though hahaha! I hope the videos are helpful to you, thank you for the sweet comment and for the support and encouragement
@geo girl, please revise the figure at 3:22. The boundary between upper shoreface and middle/lower shoreface is the the FWWB.
The lower boundary of the whole shoreface environment ends at SWWB where all evidence of wave energy whether fair weather or stormy weather ends.
This channel is pure gold
Aw this made my day, thank you! :D
As usual amazing videos..plz keep it up. I really enjoy watching your videos.
Thank s for the good information you provide, I recommend after finishing the different depositional environments and stratigraphy... to integrate between them in sequence stratigraphy (siliclastics and carbonates)
Yes! I totally agree. I actually have that in my topics plans for the future, but it'll probably be a while because that's not my expertise so I will need to do some major research haha! But I will for sure do it eventually, thanks for the suggestion! ;D
Great video! Huge help with my sedimentology report
Thanks! So glad it helped you! :D
Amazing video! It helped me to understand shoreface mechanism. It was very useful video for literature view in my master's thesis. Great Job!
So glad you found it helpful! Best of luck with your thesis! ;D
got progradation. thanks
I’m watching this before my Final Exam for Sedimentology
Good luck!
Could you make separate lecture to derive depo env from core and it will be applied part and complementary for these wonderful slides.
I LOVE your work. But is there any way to slow the speed down? I find you speak so fast that I can't keep up. I want to hear and absorb everything you say but it's just a little too fast.
Did I mention, I LOVE your work? It is helping me understand processed that I have always wanted to, and even deeper than we go in lecture. Thank you so much for doing this.
Thanks a lot! i'm studying for a final exam of Stratigrafy and this is so helpful. I'm from Angentina n speak spanish, so i have to listen it at 0.75X hahah. THNKS
I am so glad that you found it helpful! Thanks for the comment, and best of luck with your exam!! ;D
@@GEOGIRL thanks you! I'm following you on Instagram :3
@@MatiasOlate Aw, so glad to have your support on both platforms! Thank you
hi , why don’t we have preservation of sedimentary strata on coastline outcrop ? is it because erosion ?
100% yes, erosion. I am assuming you asking why there is not sedimentary outcrops on coastlines, and to that I agree with you, we don't because of erosion. I mean sometimes there are rocky coastlines but that's typically igneous rock that is harder to erode, and if it is sedimentary, it's typically partially to fully eroded or it's just a young (on geological timescales) coastline. But in general, beaches are just sandy because all that water motion (fluvial/deltaic inputs, waves, tides, etc) breaks up and erodes any rock in the area making it tiny sand grains. :)
However, if you are asking whether we have outcrops preserved of coastline depositional environments, that we do have and that is what the strat column at the end of this video shows ;)
Hope that makes sense :)
Thanks for your response.
Such an exquisitely excellent explanation, Great job< You are a Professor?
Thank you! :D I am a PhD candidate and teaching assistant, soon to be a professor ;)
@@GEOGIRL nice, you actually deserve to be one, you should be a professor 😊
May I know your expertise ? is it in sedimentary depositional systems or geomorphology things ?
@@hassanaleem2871 Nope, my specific expertise is actually in marine biogeochemistry (I work on reconstructing biological, chemical and geological processes in the ancient ocean) :D
@@GEOGIRL Very impressive wish you the best... I am doing Msc, in structural geology and active tectonics
Can you do lectures on sedimentary facies for each environment? I kind of confuse on how to classify them.
That's a great idea! I will get working on that soon!
@@GEOGIRL Thank you so much!✨
Morning madam, i have a question.
How can we interpret the fact to have sandstone with shell fragments above marine limestone in a stratigraphic log ?
Hi there, I am not sure I understand the question, what do you mean "how can we interpret the fact to have"? If you could just clarify I'd be happy to try and help! ;)
If you are wondering how sandstone above marine limestone can end up with shell fragments in it, it is because during the deposition of the sand (potentially as delta inflow or turbidity current) the flow ripped up pieces of the limestone (shell fragments) and incorporated them into the overlying sand. These are often called "rip-up" clasts. Hope that helps! ;)
@@GEOGIRL where will the double mud drapes occur; on the intertidal or subtidal environment?
@@umarmustafa6482 I am not sure what double mud drapes are as opposed to just mud drapes, but I think mud draping occurs in both the inter and sub tidal zones. The subtidal zone is more sandy, but still can have mud drapes on the sand cross beds, and the intertidal zone has more interbedded mud, so I guess if I had to choose which would have more mud draping it'd be intertidal. But you can check out this tidal depo env video for more on that: czcams.com/video/hYK2OLycFyg/video.html I made it a long time ago so I don't recall everything I used to know about tidal environments back then haha.
@@GEOGIRL thanks a lot!
Great video. Could i have the reference list?
I am so glad you enjoyed it, and the references I use are always listed in my video descriptions! :)