Paleolithic Channel settlements?

[Digit]

If we are dealing with a major glaciation I wonder how large the Moraine would be, if large enough from front to rear it would be in affect an earth damn.
All glaciers form a moraine I believe, yet melt water still flows, does it do this without washing out the moraine?

[Charlie Hatchett]

I'm guessing the carved up chalk is Cretaceous,

It is Charlie. To be fair to all who have a flood story, they are beginning to look more and more like history though.

I agree. Many different cultures have similar flood stories. Min put up a nice chart a while back delineating which cultures have a flood story and compares similar elements of each story.

Min, do you still have that chart handy?

[Forum Monk]

I as I know you are well aware, the volume and velocity required to "carve" out an area the size of the channel must be enormous. The initial water depth must be sufficient to produce the required velocities. Unless the erosion continued for a long period of time or many such events occurred like in the Missoula region and some others which occur on a fairly regular basis in Alaska or Argentina.

[Rokcet Scientist]

Its true that ice-dams form from glaciers as they block rivers and streams and when they break the results can be catastrophic. We see evidence of these events in the Pacific Northwest of the U.S. http://www.iafi.org/ and central asia.

But I think the terrain must be suited to the formation of ice-dams in the first place. I am not aware of many major ice dams which have occurred in non-moutainous regions.

You don't need mountains to form meltwater lakes, Monk. Wherever the land ice went (and it went faaar!) it left moraines (http://en.wikipedia.org/wiki/Moraine), a natural dam, which either leaked slowly or breached suddenly, releasing the huge amounts of meltwater that the land ice had left.
So meltwater lakes can just as easily have formed in lowlands.

Look at these moraines at Mono Lake, California. They would be capable of forming quite an impressive lake.

[/url]

[Digit]

Thanks RS, as my locale is surrounded by moraines I suspected that might be the case.
Monk, the erosion of the channel coasts is continuing to this day, in some areas as much as a metre a year. The chalk is very soft, hence the 'White cliffs of Dover' and the Severn Sisters. They are both dazzlingly white because they are constantly eroding, both by frost and wave action.

[Charlie Hatchett]

I as I know you are well aware, the volume and velocity required to "carve" out an area the size of the channel must be enormous.

That's why I initially mentioned the possibility of a rapid meltdown.
The chalk is fairly soft, as far as rocks go, so it's possible that moderate flow over an extended period could have created the channel.

[Digit]

The North Sea Charlie is wide and fairly shallow, unfortunately it is also funnel shaped with the Strait only some 21 miles wide. What happens sometimes is a severe storm drops the air pressure sufficintly to allow the sea level to rise noticably, if this happens to the north the water flows down hill, to the south, as the North Sea narrows the water level has been known to rise ten ft, and with storm force winds behind it even concrete sea defences have been torn apart.
The latest attempts to tame the North Sea are based on doing nothing and allowing the sea to reclaim the land.

[Forum Monk]

[/url]

What are those big things on the left and right of the picture? - they look vaguely like mountains.

I'm not saying you need moutains to form ice dams. I'm saying you need a lot of depth to create the required velocities since the speed is going to be propotional to the pressure of the water. These kinds of depths are achieved in mountainous regions as far as I know. Although I am willing to learn something new.

[Minimalist]

I recall somewhere that we had a long disussion about this whole Ice Dam thing.

In essence, they have to form high enough so that when the ice dam lets go the water flows out. So, some sort of highlands would seem to be required.

Wasn't part of the discussion the idea that glaciers start melting in the middle, thus forming the lakes?

[Charlie Hatchett]

The latest attempts to tame the North Sea are based on doing nothing and allowing the sea to reclaim the land.

Sounds like what we need to do with New Orleans.

[Forum Monk]

Wasn't part of the discussion the idea that glaciers start melting in the middle, thus forming the lakes?

That may be possible Min, over many years, but the most likely way ice dams form is when a glacier cuts across the path of a river and blocks its flow causing the water to backup behind the glacier.

[Forum Monk]

Sounds like what we need to do with New Orleans.

Careful Charlie, Houston's not exactly sitting on a mountaintop overlooking the sea.

[Minimalist]

Wasn't part of the discussion the idea that glaciers start melting in the middle, thus forming the lakes?

That may be possible Min, over many years, but the most likely way ice dams form is when a glacier cuts across the path of a river and blocks its flow causing the water to backup behind the glacier.

Why wouldn't the water behind the glacier be frozen in the first place?

[Digit]

That's correct Min I remember querying the idea of liquid water north of the 32 degree thermocline.
As I said earlier, there are the remains of a number of moraines here, but not a mountain in sight. Pass!

[Charlie Hatchett]

Sounds like what we need to do with New Orleans.

Careful Charlie, Houston's not exactly sitting on a mountaintop overlooking the sea.

True, but what's missing is the Mississippi River. Any settlement that's below sea level is in great danger in the long run.