Where does silt go

[Searush]

Maybe thats what started the problem.

I think you are correct.

IIRC, they opened up the channel on the Welsh side of the Dee trying to keep Chester open as a port - and that meant that the Wirral channel became a side channel & died. But is was a while ago, late C18, early C19 - so please forgive me if my memory is weak after all this time . . .

 

[glashen]

When I was sailing in towards the IOW this year, a ship was emptying her load just SW of the Needles.

The loads of silt from Poole that has been taken away recently year must have ended up somewhere??

Bournemouth Beach.

www.poolebay.net/PhaseI

and yes there were complaints about the quality of the material.

In Christchurch harbour some very modest dredging was undertaken and the dredged material was used to build up the banks in the harbour after a lot debate and argument.

 

[BlueSkyNick]

Believe it or not, landfill. Once you've been dredging you're not allowed to put it back in the sea.

Certainly not the case in the Solent.

In respect of Lymington & Yarmouth, its dumped between Fort Albert & Hurst Castle, on an outgoing tide.

Yep, their license constrains them to dumping between HW and HW+4.

 

[clouty]

Ssshhhh

 

[AntarcticPilot]

The long story!

Silt is simply weathered rock, and usually consists of a mixture of finely powdered silica and assorted clay minerals, along with some biological content. What happens to it is that where the energy of flowing water drops below a certain value, it slowly settles to the bottom of the water body, and builds up in layers. It may be redistributed by physical or biological agents, such as turbidity currents or the activities of burrowing animals. I guess dredging comes under the latter heading!

Anyway, over geological time, the thickness of the deposits increases, increasing the pressure and temperature in the accumulated silt. The silt undergoes the process of diagenesis, which is basically dewatering and recrystallization of some of the minerals in the sediment pile. At low temperatures and pressures, this results in rocks such as siltstones, mudstones and shales. However, if the sediment pile is moved deeper into the earth by crustal movements, the pressures and temperatures may result in complete recrystallization of the sediment, resulting is a range of metamorphic rocks whose mineralogical composition depends on the conditions that the dediments have been subjected to. Slates, Schists, Gneiss and so on are all results of this process!

If these rocks are uplifted by earth movements, then the whole process of weathering and deposition starts all over again!

So, the rock you run into in the Clyde was once a sand or mud-bank, except where it was once a volcano!