Tidal Depositional Environments & Stratigraphy | GEO GIRL

Tidal depositional environments are regions along ocean margins where tides strongly influence the deposition of sediment and formation of sedimentary structures that get preserved in the rock record over geologic time. In this video, I cover tidal processes and deposition, as well as the sedimentary structures and stratigraphy formed by tides, with both modern and ancient examples of tidal environments and the structures that form in these systems. We start by discussing the difference between waves and tides and the difference in wave influence on sediment movement and deposition compared to tidal sediment transport and deposition. I then move on to the difference between spring and neap tides and the difference in the spring tide sediment load relative to the neap tide sediment transport and deposition which is much weaker than spring tides. I also go over tidal range in various regions of the world, where tides are the largest and where they are dirunal. Then we jump into tidal sedimentary structures, such as laminations, cyclic rhythmites, tidal dunes, compound ripple marks, lenticular, wavy, & flaser bedding, and the difference between flood and ebb deposition. Finally we go over the bedforms formed by tides, such as tidal flats, tidal deltas, tidal estuaries, tidal bars, etc. Lastly, I show the stratigraphic columns that we expect to see in rocks that were deposited in tide-dominated environments, as well as some trace fossils (ichnofacies) that may help you recognize tide depositional environment in the field.
References:
Depositional Sedimentary Environments: amzn.to/3sSXxKZ
Facies models 4: amzn.to/3sSXyyx
dx.doi.org/10.1007/978-94-007-...
doi.org/10.2110/jsr.2018.28
doi.org/10.1016/j.sedgeo.2012...
doi.org/10.1016/j.sedgeo.2012...
dx.doi.org/10.2110/pec.98.61.0095
dx.doi.org/10.2110/pec.03.76.0147
doi.org/10.1007/978-94-007-01...
dx.doi.org/10.3923/jas.2017.2...
www.researchgate.net/publicat...
www.researchgate.net/publicat...
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!)
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0:00 What affects tidal environments?
0:39 Tides vs. waves?
1:57 What causes tides?
2:45 Spring vs. neap tides
4:20 Tidal range
5:22 Where are tides the largest? Smallest?
5:47 Tidal deposition/laminae/rhythmites
7:45 Tidal sedimentary structures (flood vs. ebb tides)
11:09 Tidal dunes and ripples
13:42 Preserved tidal dune outcrop
14:20 Lenticular, wavy, & flaser bedding formed by tides
15:56 Tidal environments: tidal deltas
16:54 Tidal environments: tidal estuaries
18:38 Tidal environments: tidal flats
19:34 Tidal stratigraphy
20:19 Tidal dune stratigraphy
20:41 Tidal channel stratigraphy
21:16 Trace fossils in tidal depositional environments
Image sources:
doi.org/10.1007/978-94-007-01...
www.amazon.ca/Facies-Models-R...
smallpond.ca/jim/sand/migrati...
doi.org/10.2110/jsr.2018.28
www.researchgate.net/profile/...
www.slideshare.net/wwlittle/b...
www.researchgate.net/publicat...
www.marinebiotech.eu/wiki/Wave...
www.researchgate.net/publicat...
www.sepmstrata.org/page.aspx?p...
wessexcoastgeology.soton.ac.u...
www.researchgate.net/publicat...
www.researchgate.net/figure/R...
www.researchgate.net/publicat...
seddepseq.co.uk/depositional_e...
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[@davidrogers8030]

Excellent stuff. Incidentally, best in-depth prog just on tides I've seen was a preMatt PBS SpaceTime.

[@AdeleAllFans]

I am going to write my geology exam tomorrow. You really helped me to understand tidal flows. Thank you very much.❤❤

[@GEOGIRL]

So glad you found the video helpful. Best of luck on your exam!

[@EmmanuelMthombeni]

which university are you in?

[@AdeleAllFans]

@@EmmanuelMthombeni Wits University in South Africa

[@danial_amini]

thank u rachel I just started reading up on tidal sediment transfer and this was a great help!

[@GEOGIRL]

You are most certainly welcome! I am so glad I could help ;)

[@Fifi980803]

Love your enthusiasm! Sending love from another Geo Girl here 💕

[@GEOGIRL]

Thanks so much! ;D

[@adammohammed6632]

very informative video,thanks alot, could you make a video about how to draw stratigraphic charts, as well as continuing the videos on depositional environment,plus giving some insights about the hydrocarbon reservoir potentiality of different depositional environments

[@Evander.christianusTukon]

Thank you for the explanation darling, I now understand 🙏♥️

[@hassanmasoud2023]

that wsa an informitive. thaks and keep it up .

[@GEOGIRL]

Thanks, so glad it helped you!

[@Dragrath1]

Technically all water experiences tides its just that except for really large lakes bordering on full fledged seas, the effect of tides is too small to be observed. This is because rather than the actual tide what we experience is the amplification it is the size of a body of water which is largely responsible of amplifying tidal influences due to hydrogen bonds pulling on each other. As a result this effect is directly proportional to the amount of water in a body of water which can slosh around amplifying the tidal effect. Without this effect the strength of lunar not to mention solar tides would be relatively tiny which is why we don't really have to worry about tides in other substances like rocks the way Io does. Oh and tidal forces depend on a -2/r^3 relationship rather than the normal 1/r^2 gravitational force because tidal forces are the derivative of gravitational forces.

[@nhcphantom2411]

It is almost perfect but your subtitles effects covering all the imp diagrams and points... Please use default subtitles 🙌

[@GEOGIRL]

I think you can turn them off ? I didn't put any subtitles, so it is probably showing whatever subtitles were automatically generated by KZbin, I think they may have size or placement options if you click on the settings icon in the bottom corner. Sorry about that!

[@jidepan-okafor8209]

Very helpful.

[@GEOGIRL]

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

[@abdulwahabbello9260]

Excellent video! Thanks so much. Could you please do a video on deep-water turbidites and depositional facies? Thanks in anticipation.

[@GEOGIRL]

I have one on that topic! -> kzbin.info/www/bejne/a5fZoZqbaLCkfJo Let me know if it answers the questions you are having about turbidites! ;)

[@amanmehta2161]

Loving ur videos providing exact information i need I request u to make next videos on types on landforms

[@GEOGIRL]

Sounds great, thanks for the input! What landforms were you thinking about? And what kind of information about them would you like?

[@amanmehta2161]

@@GEOGIRL thanks for ur reply Types of landforms like fluvial, glacial, karst just brief about evry type in video including there depositional and erosion effects will be very helpful

[@GEOGIRL]

@@amanmehta2161 Cool, I will start working on that!

[@amanmehta2161]

@@GEOGIRL Thank you That would be very kind of you

[@moubarackosseni5005]

hi rachel , how does wavy , flaser and lenticular bedding are formed ? what is the meaning of the transition from wavy to flaser bedding ?

[@GEOGIRL]

Wavy, flaser, and lenticular bedding can all be formed by tides (flood current picks up and deposits sand then suspended mud is deposited during transition from flood to ebb current). A transition from wavy to flaser bedding (more to less mud) indicates a transition to a higher flow regime (stronger current) that is able to pick up more sand. Hope that makes sense ;)

[@syafeeqazly6628]

You're so beautiful.