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Why Do Rivers Have Deltas?

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Where rivers meet the ocean, coastlines tend to bend either inward or outward, creating estuaries and deltas. But how do they get those shapes? A huge thank-you to the following organizations, all working toward sustainable deltas, for sponsoring this video: the Belmont Forum, the Sustainable Deltas Initiative, the National Center for Earth-Surface Dynamics, the St Anthony Falls Laboratory of the University of Minnesota, and the DELTAS project. These organizations study deltas around the world, in particular how they’re threatened by human activities such as building dams, channelizing rivers, and climate change-induced sea-level rise. If we don’t pay attention, we might lose the landform that allowed us to become civilized in the first place. Thanks also to our Patreon patrons: - Today I Found Out - Jeff Straathof - Mark Roth - Maarten Bremer - Tony Fadell - Antoine Coeur - Nicholas Buckendorf - Alberto Bortoni - Valentin - Muhammad Shifaz ___________________________________________ Want to learn more about the topic in this week’s video? Here are some keywords/phrases to get your googling started: – delta: the piled-up sediment (typically triangular, or greek-letter-delta-shaped) deposited by a river as it flows into a larger body of water – estuary: a partially enclosed body of brackish (part salt, part fresh) water that connects one or more ocean-bound streams/rivers to the open sea. Geologists classify estuaries into four basic types (bar-built, coastal plain/drowned river, tectonic, and fjord), based on the geologic processes that formed them. – ice age: this is a term that geologists use a little differently than non-scientists. Geologically speaking, an ice age is a fairly long period (~100-300 million years) of relatively cold temperatures on Earth. Within these long periods of time, the climate warms and cools lots of times, causing the ice sheets to retreat and advance; geologists refer to the colder time intervals as "glacials" and the warmer periods as "interglacials". We are currently in an "interglacial" phase (that started ~15,000 years ago) of an ice age that started ~2.6 million years ago, but because that's kind of complicated, we just say "the end of the last ice age" when what we really mean is "the end of the last 'glacial' cycle of the current ice age." – marine transgression / marine regression: on the surface, these are just fancy ways of talking about sea level going up and down. But for geologists, "transgression" and "regression" are more useful, because land sometimes goes up and down too. For example, if movement along a tectonic fault causes part of the coast to drop below sea level, it might get flooded, but it wouldn't be accurate to attribute the flooding to sea level rise. So geologists describe the situation as "marine transgression" instead. These terms comes in handy when we're talking about deltas and estuaries: deltas are formed by marine regression, and estuaries by marine transgression. ___________________________________________ Credits (and Twitter handles): Script Writer: Emily Elert (@eelert) Script Editor: Kate Yoshida (@KateYoshida) Video Illustrator: Omkar Bhagat (@TheCuriousEnggr) Video Director: Emily Elert (@eelert) With Contributions From: Alex Reich (@alexhreich), Henry Reich (@minutephysics) and Ever Salazar (@eversalazar) Music by: Nathaniel Schroeder: http://www.soundcloud.com/drschroeder _________________________________________ Like our videos? Subscribe to MinuteEarth on YouTube: http://goo.gl/EpIDGd And for exclusive early access to all our videos, sign up with Vessel: https://goo.gl/hgD1iJ Already subscribed? Help us keep making MinuteEarth by supporting us on Patreon: https://goo.gl/ZVgLQZ Also, say hello on: Facebook: http://goo.gl/FpAvo6 Twitter: http://goo.gl/Y1aWVC And find us on itunes: https://goo.gl/sfwS6n ________________________ References: Bhattacharya, J.P. (2003) Deltas and Estuaries, In: Middleton G.V. (editor) Encyclopedia of Sedimentology, Kluwer Academic 145-152. http://www.geosc.uh.edu/docs/geos/faculty-files/pdf/2003.pdf Day, J., Gunn, J., Folan, W., Yáñez-Arancibia, A., & Horton, B. (2007). Emergence of complex societies after sea level stabilized. Eos Trans. AGU Eos, Transactions American Geophysical Union, 88(15), 169-170. Giosan, L., Goodbred, S.L. (2006) Deltaic Environments. Encyclopedia of Quaternary Science. https://www.whoi.edu/science/GG/coastal/publications/pdfs/Giosan&Goodbred_DeltEnv_REVISED.pdf Gupta, A. (2007). Large rivers: Geomorphology and management. Chichester, England: John Wiley. Russell, R.J. (1967) Aspects of Coastal Morphology. Geografiska Annaler. Series A, Physical Geography 49: 299-309. (Abstract) http://www.jstor.org/stable/520896?seq=1#page_scan_tab_contents Wright, L.D. (1977) Sediment transport and deposition at river mouths: A synthesis. Geological Society of America Bulletin 88:857-868.
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Text Comments (826)
Lachlan Zyp (7 hours ago)
when a 2 minute video teaches you more than a 2 hour class
Sherry Marshall (2 days ago)
I have an innie
Rahul Singh (4 days ago)
This is helpful to all students
Jacobo Hernandez Erazo (22 days ago)
I like the video
B1209Y (24 days ago)
Adriano Marçal (1 month ago)
OMG, the narrator speaks so fast that I had to activate the caption to understand it better.
Charise Bago (1 month ago)
I♡ sentuary
DragonKnightdragons (1 month ago)
I’m an inny
cherry Cute (1 month ago)
is shark older than the dinasour
Muaz Yusuf (2 months ago)
Ziad Baha (2 months ago)
I have none of those
Dexter Gaming (2 months ago)
My friend has outs
Saturn (2 months ago)
So u want to say those rivers who has estuaries at meeting point are newer than those who have deltas
me nitin (3 months ago)
Bhut accha English bolte ho baba
Hayemaker101 Slugger (3 months ago)
Anyone here for year 8 geography
Blue 913 (3 months ago)
Fractal rivers! =)
Big Chungus (3 months ago)
The first 5 secs tho
Scott Anderson (3 months ago)
But what about gorilla belly buttons
Comedy kut !!! (3 months ago)
Because God Said so thats why gays are bad and buttsexgood
Chazzz Tube (3 months ago)
Thanks so much man know I get about deltas for my science test next can you make a vid about weathering erosion and deposition
Shadowolf Gacha (3 months ago)
I live in the Mississippi delta
Nate (4 months ago)
800th comment
Nate (4 months ago)
M W (4 months ago)
If the earth is millions of years old ........where is all the sediment?
Jane Xemylixa (3 months ago)
Geologists were puzzled by that in the early 20th century, too. Turns out it goes back into Earth's mantle via a process called subduction.
James Currie (4 months ago)
I live in a city called Delta witch is located on a delta
A Person (4 months ago)
WTF this is not a minute long... false advertising...
WegDhass (4 months ago)
80% commenting about outies 17% commenting about innies 3% commenting about the video
adam hill (4 months ago)
absolut crap
Milan Gogoi (4 months ago)
please upload more snd more videos
The Official V (4 months ago)
ricecristi (5 months ago)
I call mine an inbetweenie bc it’s not an outie or an innie 🤔
Muddy Buddy (5 months ago)
Divya Chugh (5 months ago)
you are speaking soooooo fast ...express speed. Slow down else its of no use for the age group who needs this info.
Bob Elschlager (5 months ago)
Stated a bit fast. But if u stop the video and play parts of it several times, calmly, u can pick up some of the material.
Sam T. (5 months ago)
why are rivers made of water, and not jello?
MYHNEA (5 months ago)
VoTkA T-T (5 months ago)
1:45..where is the Danube delta?
Devansh Patel (6 months ago)
lilo dawg (6 months ago)
Save trees and recycle!! ;)
Sancy Mb (6 months ago)
Thank you..
Prasenjit Bhattacharya (6 months ago)
Ganga bramhaputra delta is the largest in world
Delta Animation (6 months ago)
I only click on this because delta is in my Yt name ._.
Hellbanisher Rockz (7 months ago)
Those are not belly buttons they are tiny ears
Buahball (7 months ago)
Because they had charlies
Widget (8 months ago)
Ain't geography cool?
SCOUTSOUT (8 months ago)
Spark Beggs (8 months ago)
i have a innie
Haja Modhvadia (8 months ago)
MC Dimension (9 months ago)
GamingGirl (9 months ago)
Chintu Gulia (9 months ago)
but u are speaking completely in high level English so some difficult to understand... 😯😑😐🤔🙄
Chintu Gulia (9 months ago)
nice sir
spitfire (9 months ago)
Because god was bad at ms paint
Franky Munoz (9 months ago)
the barrier island in the Gulf of Mexico comes from dirt and sediment that create them
K mad (9 months ago)
Love the analogy in explaining what a delta is.
Vince van D (10 months ago)
You made my belly button itch
OGMadari (10 months ago)
outie bellybuttons look fucking disgusting
pipolwes000 (10 months ago)
So if there had not been an ice age (tens of) thousands of years ago there would not be any rivers with "innie" mouths?
Sirji Singh (10 months ago)
Can you do a video on River Capture/ Stream Piracy??
Rain maned wolf !!! (10 months ago)
Alegost1 (10 months ago)
does that mean that any river if it exists long enough will form a delta?
Asmus Aner storm (10 months ago)
why did you have to make this about bellybuttons?
Jagannadha Rao (10 months ago)
OK then How do you explain the inland Deltas like the Okawanga Delta of Botsawana?
Rameen Aminlodhika (11 months ago)
a great video but u were very fast
I hate people with outies
PRODUCER NASH (11 months ago)
nice exp
Ieuans Gamingstation (11 months ago)
you get a inny/outy from when doctots cut the tube feeding you in your mothers womb
Ann Welter (11 months ago)
Mysterious Catuber (11 months ago)
That means poking out river mouths comes from inni river mouths? Inni to outie?
Yaseen Shah (11 months ago)
Forgot to put dot @ Indus Delta. Very Disappointed!
Gurmeetsingh Mehtab (11 months ago)
Amazing one! Such a simple way to explain something so vast. Thank you!
Peeble Kitty (11 months ago)
Unlike their airline counterparts, Deltas are really cool. Especially the smaller, tree-looking ones with little sandy streams.
Roef van Hassel (1 year ago)
Je vader
Jax Matthews (1 year ago)
I have an Innie navel
Null (1 year ago)
My geography teacher showed this in class. For some reason everyone freaked out when the belly buttons came up.
Julius Bernotas (1 year ago)
I was taught at school, that river deltas form where is a little variation between high and low tide, so the sediment doesn't get washed off. You can notice that most rivers that flow into open ocean have wide estuaries, and those which flow to closed seas (i.e. Caspian, Mediterranean), tend to have branchy deltas. Exception would be Ganges - Brahmaputra, which has huge delta, but empties basically into open ocean.
Ryan de Bruin (1 year ago)
People don’t get taught this in high school?
Domas Smaliukas (1 year ago)
But now you have to explain the belly button thing.
Rome Blanchard (1 year ago)
What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps, has a bank but never loans, has an innies and outies but got no belly button?
Ur mom
The Ash Tray (1 month ago)
A depressed antisocial college student
Ponso Dioso (1 month ago)
+EVA_Unit_4A 0ep
WHY NOT (1 year ago)
Because they made a delta get some noice wootah
Thomas P (1 year ago)
So , what determines if the river delta will be "innie" or "outie"? The flow conditions that allow sedimentation?
Pinkie Pie (1 year ago)
Can u make a video about " PHYSICAL CONDITIONS OF SEASHORE AND AN ESTUARY " ? Please For my Assignment in Science! 😊😊😊
12345 678910 (1 year ago)
what about backwaters of kerala india?
PARTHASARATHI Ghosh (1 year ago)
u make geography fun and interesting for my little daughter.
Matthew M (1 year ago)
I thought it had something to do with united.
Dani Groot (1 year ago)
or you just build one like the dutch in the port of rotterdam
red CORAL (1 year ago)
Best explanation ever
CodeName:CYT (1 year ago)
0:20 this remind me of groudon vs kyogre
Guilherme Suzano (1 year ago)
Nice explanation of a tide dominated delta! You could go beyond and explain about types of estuaries and other deltas. Thank you!
Merlin Ambrosius (1 year ago)
Yikes The name makes no sense But ending up with those horrible jokes about me
Maurizio Pavel (1 year ago)
Danube Delta anyone? No? ok...
Danillo Rodrigues (1 year ago)
innies bellybutton master race
In 0:07 it is a belly button its's a inny and outty
Why are you conpairing belly buttons with rivers? 🏞️
theflynn2sout (1 year ago)
Like, Mississippi Delta.
WTF GAMER (1 year ago)
I had an ad before this that was about this No joke it was a coincidence
Braniya Willis (1 year ago)
this is a bad cringy video
gameing survivor (1 year ago)
Stockholm has tat in the End and a live there

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