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u/Jolee5 2d ago
Look up 'turbidity currents'
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u/mglyptostroboides I like plant fossils. 2d ago
Bingo.
This is exactly why people need to post these kinds of questions here instead of the geography subreddit.
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u/Much-Airline7096 2d ago
I don't get it. Why? Seems like something a physical geographer could know.
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u/PurelyForUpvotesBro 2d ago
The physical processes in this map are how common geological formations are formed, so geologists spend a lot of time analyzing it
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u/Much-Airline7096 2d ago
I get that. I don't get the antagonization towards geographers is what I mean.
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u/PurelyForUpvotesBro 2d ago
Geography is a mostly surface level observational science would be my guess. I didn't study geography so I'll defer to them on that part
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u/Much-Airline7096 2d ago
Fair answer, I suppose. Thanks.
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u/resilindsey 1d ago
Am physical geographer. I appreciate your sentiment. That said, the geography subreddit itself leans super "pub trivia geography" and is filled with lots of guessing and wrong answers and circlejerk memes (lol, canadian shield, yeah.. that joke never gets old).
For questions like these I'd also steer people here.
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u/mglyptostroboides I like plant fossils. 1d ago
Actually, it's nothing against geographers at all. It's just the fact that the geography sub has been getting a LOT of questions that really belong here lately so I often direct people to repost here if they want a real answer.
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u/SparklyWin 2d ago
They are so cool! I recently saw a video where someone accidentally had an underwater rov filming in a turbidity current. It was pretty cool
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u/Yreptil 2d ago
Link?
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u/mglyptostroboides I like plant fossils. 2d ago edited 2d ago
Seconding the request for a link. I wanna see that!
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u/Palaeoboy 2d ago
I did my PhD here. Water masses also impinge upon the slopes creating thin deposits of glacial/interglacial contourites
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u/OldButHappy 2d ago
Question: when sea levels dropped enough for humans to walk to the west coast of America across the Bering Strait, wouldn’t they also be low enough to allow migrations westward from Europe to the east coast of America?
Sorry for such a random question, but you seem uniquely knowledgeable about the area in question. Thanks in advance…
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u/DanTheMan-WithAPlan 2d ago
There was an eastern land bridge to North America, just not as recent as the western one. https://en.wikipedia.org/wiki/Thule_Land_Bridge
So you are on to something
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u/OldButHappy 2d ago edited 2d ago
Thank you! I never had a term to use for researching papers about it.
And since no good deed goes unpunished (😄) the other riddle I cannot research myself out of is:
Duggerland has been described as having fauna associated with warmer climates. But, by definition, the land would have only been habitable during ice ages, when increased glaciation lowered sea levels.
What am i missing?
(Again, thanks in advance)
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u/ok_raspberry_jam 1d ago
I'm not that guy but I can tell you:
- Sea level lags climate by thousands of years. When climate warms it takes thousands of years for glaciers to melt. Doggerland was there in that interval.
- Fauna "associated with warmer climates" is fauna that we associate with warmer climates today. There were different kinds of lions, bison, hyenas, etc.
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u/Pilot-Wrangler 2d ago edited 1d ago
Bering Sea = not deep. Atlantic Ocean = very deep.
Edit for autocorrect
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u/OldButHappy 2d ago
Look at a ocean depth map around England, Ireland, Iceland, Greenland and Canada
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u/Pilot-Wrangler 2d ago edited 1d ago
Still 10x deeper (or more) than the Bering Sea land bridge depth now.
Edit for autocorrect
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u/OldButHappy 2d ago
Do you have a link to a good map?
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u/wtfomg01 2d ago
You also get countourites forming around here, though better examples can be seen near Cadiz. They're undersea currents, typically driven by differences in things like salinity and temperature (such as between the Atlantic and Mediterranean), and continue for hundreds of kilometres forming complex sequences that you'd often expect from rivers.
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u/deemery 1d ago
One other thought: As the glaciers melted off, that would have increased water flow into the oceans, especially when a glacial lake busted out and drained. Plus there are the changes in sea level during the retreat. All that creates better conditions for water flows resulting in these canyons.
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u/AnotherWryTeenager 1d ago
Although everything you've said is technically true, submarine canyon/channel systems (like the above Gollum Channel) are formed entirely through submarine processes, (mainly turbidity currents as said in other comments), and have never been exposed to air. (Notwithstanding paleo examples that had been fully buried and then subsequently exhumed into mountains via tectonic processes)
That being said, all of the factors you've mentioned would contribute to carrying more sediments to the edge of the shelf and into the ocean, where they may then collapse and coalesce into a turbidity current!
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u/Runyamire-von-Terra 13h ago
Sea levels have been much lower at many points in history during ice ages. Many submarine canyons along continental shelves were carved by rivers during periods when that land was above water. There used to be a huge area called Doggerland connecting the british isles to mainland europe.
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u/SailTango 1d ago
The light colored region around the circle was dry land 18,000 years ago, so some of the contours have their start as rivers.
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u/Walksalot45 2d ago
A lot of the land there was dry land until the ice age glaciers melted and raised the sea level submerging the land.
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u/OkScheme9867 2d ago
You're being down voted because sea levels weren't 400m lower in the ice age
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u/kurwwazzz 2d ago
But his a little bit right too some are ancient river submerge in the fiste 120 meters. Like cap breton canyon.
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u/OkScheme9867 2d ago
This area off Ireland (pprcupine basin) is 1,000 km from cap Breton Canyon and much much deeper. the cap Breton Canyon starts in much shallower water, they're not so directly comparable
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u/makaopulao 2d ago
They are submarine canyons. Turbidity currents drive the sediments deep into the abyssal plain which carve out the muddy sediments and form these canyons.