What caused Heracleion to sink 150 feet below sea level?

[Andre]

This thread is a present for Evo's birthday

There was some media coverage of Heracleion here and here the other day.

Check out the links, awesome photo's.

Submerged under 150 feet of water, the site sits in what is now the Bay of Aboukir. In the 8th Century BC, when the city is thought to have been built, it would have sat at the mouth of the River Nile delta as it opened up into the Mediterranean.

Scientists still have little idea what caused the city to slip into the water nearly 1,000 years later, but it is thought that gradual sea level rise combined with a sudden collapse of the unstable sediment the city was built on caused the area to drop by around 12 feet.

However the global sea level rise in the last 3000 years was maybe three feet, so only 15 feet would be accounted for. It's geologically interesting to find out what *exactly* was responsible for the other 135 feet.

 

[Evo]

As soon as I saw the thread title, I had to look. Thank you!

 

[davenn]

cool links Andre thanks
a nice bit of underwater video in that second link

Happy birthday Evo :)

Dave

 

[viryan23]

This thread is a present for Evo's birthday

However the global sea level rise in the last 3000 years was maybe three feet, so only 15 feet would be accounted for. It's geologically interesting to find out what *exactly* was responsible for the other 135 feet.

It is really interesting... You know, about finding the missing pieces of our history. Well, I find the some part of the Scientists explanation sensible - the gradual sea level rise combined with a sudden collapse of the unstable sediment. Just a guess about the 135 feet rise of the water level, it might be due to the change of the course of the water; that one day, the people wake up and find the waters of the river begin flooding into their city.

 

[johnbbahm]

I will throw something out for a try.
As the Nile eats away at Africa, the matter carried down changes over time.
Let's say 10,000 years ago, a large flood picked up and deposited a large amount
of somewhat stable clay.
The nature and viscosity of the clay, let the river extend a finger of land out into the sea
with rather steep sides.
The area appears stable, but has steep sides.
The land is desirable as the deep water comes right up to the shore, without any reefs.
Some geological event causes the river to alter it's course, and now the river begins
eating away the foundations of the entire spit of land.
At some point the entire piece of land slips off the precipice into much deeper water.