The geology of Anglesey

© Craven & Pendle Geological Society

Marquess of Anglesey's Column

Marquess of Anglesey Column

Blueschist (SH 535 715)

As you cross the Brittania Bridge onto Anglesey you can't fail to notice the upstanding landmark known as THE MARQUESS OF ANGLESEY COLUMN set upon an ancient hill-top fort on the outskirts of Llanfair PG. The column (minus statue) was finished two years after the battle of Waterloo on the 18th June 1815. The statue was added in 1860 following the death of Henry William Paget, the first Marquess of Anglesey.

Although the column is built of limestone, this site is better known for the Anglesey blueschist - the most accessible exposures of blueschist in Great Britain. It is exposed in a series of rocky crags in woods beneath the Column. The rocks are fine-grained, foliated and lineated, dark blue-grey schists.

Blueschist is an unusual metamorphic rock that is produced by subduction of oceanic crust. The occurrence of blueschist prior to the Mesozoic is rare so it's possible that the Precambrian Anglesey blueschists are perhaps the oldest recorded blueschists in the world. The presence of blue glaucophanic amphibole is usually associated with rocks subducted at ocean trenches where high pressures and low temperatures are the norm. This site is of international importance so no hammering please!

Blueschist

The column is sign-posted off the main road and there is ample coach and car parking. If you attempt the climb up the column there are 115 steps. Your efforts will be rewarded with fantastic views of the Menai Straits and the mountains of Snowdonia.

There is a WC and opening times are ALL YEAR: each day from 9am to 5pm. As of 2005: Adults £1.50, Child / Senior Citizen at £0.75