Estuary Depositional Environments & Stratigraphy | GEO GIRL

[@meahrey]

Taking Oceanography rn, thank you!

[@blacktouch6532]

Hi. How we can make différence between à sand massif in the tidal bar and sand massive in the turbidite environnement

[@GEOGIRL]

Well turbidites are great because they often contain a very distinct sequence of layers and sedimentary structures (see my turbidite video for more: kzbin.info/www/bejne/a5fZoZqbaLCkfJo). So I would say the easiest way to tell whether you are looking at turbidite vs tidal is see if the sand has ripples, if so, are the ripples unidirectional or bidirectional. If bidirectional, then it's tidal. If unidirectional, you need more information. Then look for the layers above and below the sand. Is it coarser below and finer above (a fining upward sequence)? Then probably turbidite. Then look at the fine or muddy contents: if mud layers are interbedded with the sand in rhythmic sequences, then probably tidal, but if mud layers clearly overlie the sand as the sequence fines upward, then probably turbidite. What about sedimentary structures other than ripples: is there any trough cross stratification or hummocky/swaley cross stratification, if so, then probably turbidite, if not, then probably tidal. Tidal environments are much lower energy than turbidity currents, so they aren't able to produce those sedimentary structures, at most they may be able to produce planar cross strat but that's about it. I have a video all about sed structures coming out on the 27th of this month, so I hope you'll stick around for that, I think it will help to visualize these things :)

[@dr.ahmeda.kassem394]

@@GEOGIRL Let me first thanks for your efforts and great explanation. Really I recommend your videos to all of my colleagues and students. You said here that the turbidite has hummocky/swaley cross stratification, Could you explain more. Because I think if I have HCS, I suggest to have lower/middle shoreface? Thanks again

[@mazenomar7279]

When the river flow into sea it formed delta and also it formed esuarine ,so based on wihich situation is formed delta or estuatine.

[@GEOGIRL]

Great question! Deltas typically form when the input into the region is more river dominated than ocean (wave & tide) dominated; whereas an estuary forms when there is both wave/tide and river input. :)

[@mazenomar7279]

@@GEOGIRL Many thanks

[@CarlosAlvarez-cf9io]

Hi Geo Girl! You have excellent videos! Thanks for sharing them! I would like to look for fossils in my country. Which books would you recommend me to study to be able to identify Sedimentary Structures and Depositonal Environmentes in rocks so that it is easier for me to know where to look for fossils?

[@GEOGIRL]

HI Carlos, thanks for the kind words and support! I think the book at this link: www.amazon.com/World-Encyclopedia-Fossils-Fossil-Collecting-Illustrated/dp/1780193947 is a great overall book to have for fossil collecting and it's not crazy expensive, which is always nice. However, for general geology (sedimentary structures and depo environments), it would be helpful to know the country or region you have in mind. What I would probably do is search in google "geology of *then put the region you are interested in*". And for your purposes it may be helpful to look for one that says 'field guide". However, if you just want a general book (not region specific) for identifying depo environments and sed structures, I would recommend www.amazon.com/Principles-Sedimentology-Stratigraphy-Sam-Boggs/dp/9332570957/ref=sr_1_1?crid=84TNBZPTW3TL&dchild=1&keywords=sedimentology+and+stratigraphy&qid=1609287106&s=books&sprefix=sedimentology+and+%2Cstripbooks%2C177&sr=1-1 for a general background on sedimentary geology, but this is not super detailed when it comes to depositional environments and how to recognize them. For a detailed depo environment book I really like these two: www.amazon.com/Facies-Models-Noel-P-James/dp/1897095503/ref=sr_1_1?dchild=1&keywords=facies+model+4&qid=1609287321&s=books&sr=1-1 www.amazon.com/Depositional-Sedimentary-Environments-Reference-Terrigenous/dp/3540101896/ref=sr_1_1?dchild=1&keywords=sedimentary+depositional+environments&qid=1609287282&s=books&sr=1-1

[@Evander.christianusTukon]

Thank you for giving me knowledge 🙏😊

[@Ilemaurice687]

Hello do u know about marine environnement too?

[@GEOGIRL]

Yep, I have some videos out about the marine environment. I have a recent one out about organic matter burial and diagenesis in marine sediments: kzbin.info/www/bejne/jZPZaqWIp7Zgldk. I also have this depositional environment video about submarine fans: kzbin.info/www/bejne/a5fZoZqbaLCkfJo. And I also have a lot more coming out about the geobiology and geochemistry of marine systems in the future, if you have topic suggestions for marine environment videos I should do, please let me know :D Thanks!

[@victorarnault]

Thank you.