A Sequence of Rocks (up to 1300metres thick) , between Dinas Island and Cemaes Head ,
are classed as Turbidite Sandstones and Mudstones , layed down over a few years about
440 million years ago.
Sedimentary Debris - Sand, Gravel and Mud - accumulated in great banks, forming unstable masses above the slopes leading down into the deeper water. Frequently, large
portions of these sediment masses would slide, at first slowly and then, as they gained
momentum down the slope, as colossal fast-moving submarine avalanches.
These fanned out to cover vast areas of the seabed, time and again, layer upon layer.
Every Sand-Silt-Mud sequence representing a single submarine avalanche.
The pic shows the Heavily Folded Turbidite Rocks at Ceibwr Bay
with a Blowhole shooting water into the Air.
These Turbidited Rocks can be seen at close quarters at the RIGS - Newport Sands
( East of the Parrog to the Iron Bridge) and Poppit Sands (Cei-Bach to Trwyn Careg-ddu).
This Type of rock can also be seen particularly well in the sea-cliffs at Aberystwyth.
Ref: 11001
Date: 21/10/2012
Location: SN 108.458
