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CLEVEDON, Ladye Bay to Walton Bay

22.06.24

Leader

Mark Howson

Category

Geology

Date

22nd June 2024
10:30 am -

Location

Open Maps

The trip will involve a walk along the coast to Walton Bay and return, a distance of about 5kms, to examine the Devonian and Triassic sequences exposed in the cliffs and foreshore.

At Ladye Bay, we will see Late Triassic Oolites and Devonian sandstones of the Portishead Formation. Walking along the coast path to the NE there are conglomerates of the Mercia Mudstone Marginal Facies (MMMF), also known as the Dolomitic Conglomerate and its unconformity with the Devonian sandstones below.

We will also see baryte mineralization and a rock arch that may be natural or producedby historical coastal quarrying. At Walton Bay, there are interesting springs and a cliff section that shows the erosion and repose angles of the onlapping (MMMF). Earlier this year there were reports of a ‘landslip’ at Ladye Bay.

Mark Howson visited the site on 24th March and found that the council had erected three barricades on the coast path to close access to the bay, and a sign said that the closure order, dated 23 February is for 21 days. However, since then, beach and path users have beaten paths round the barricades and they can be easily negotiated. Indeed, there were several groups of people enjoying the beach and walking along the coast path. From the beach. I observed that a minor, natural rockfall from the cliff has produced a pile of rock debris beside the steps onto the beach, but not impeding access. To describe the fall as a
‘landslip’ stretches credibility, and I did not see evidence of recent larger-scale structural failure in the cliff that may presage a larger landslide. I interpreted that the fall was initiated by vegetation roots growing into rock joints at the top of the cliff. The section of coast path above the cliff that could possibly be at risk is very short and far shorter than the length implied by the council’s (ineffective) barricades. The pile of fresh rock that the fall has produced is geologically interesting, featuring micaceous sandstones.

The path and access to the foreshore is rocky, slippery or muddy at times, and in one or two places a little scrambling will be necessary, so wear stout boots and water/wind proof clothing, and, I suggest, leather or gardening gloves. Bring packed lunch and refreshments.

A hard hat is advisable for examination of the rock pile, as it is for any geological examination near cliffs.

Meet 10.30am at Ladye Bay (street parking), Clevedon, Post Code BS21 7BU, Grid Reference ST 408 728.

Please contact Mark Howson, by completing the form below, if you wish to attend.

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