Ardnamurchan lighthouse – Lochaber Geopark display

The journey

In addition to our visitor centres in Fort William and Roybridge, Lochaber Geopark has an exciting display in an out-house of the light-house at Ardnamurchan Point, part of a visitor centre run by Ardnamurchan Lighthouse Trust.

Ardnamurchan, the ‘Headland of the Great Seas’, is a magical place, the most westerly point in mainland Britain. Climb the lighthouse and you will see one of the grandest views in the British Isles, stretching from the Isle of Mull in the south to the Isles of Muck, Eigg, Rum and Skye in the north.

Ardnamurchan Point, the Headland of the Great Seas

The Great Seas from Ardnamurchan lighthouse, with a nice, cosy café below at the left.

The Sea of the Hebrides from Ardnamurchan, with the Isle of Eigg on the left, and the Cuillin mountains of the Isle of Skye forming the distant sky-line.

Ardnamurchan lighthouse is a full day out from Fort William. The most direct route is to go South on the A82 and take the Corran ferry to Ardgour. Although the total outward distance is only 58 miles, much of the journey is along single-track roads with passing places and the estimated time is 2 hours and 16 minutes, not including the ferry.

The journey will take you through the village of Strontian, after which the chemical element strontium is named. Interpretative panels in the village square tell the story of the 19th century lead-mining that revealed a new mineral, subsequently named strontianite, from which Humphry Davy extracted strontium.

Continuing west you will reach Kilchoan, the most westerly village in mainland Britain. From here you can take the car ferry from Mingary Pier to Tobermory, on the Isle of Mull, or continue the remaining 6 miles to the light-house. It was designed by Alan Stevenson, who was the uncle of the writer Robert Louis Stevenson, and a member of a family who built lighthouses around the UK over a period of 150 years. Opened in 1849 and constructed of perfectly shaped blocks of granite from Mull, it is a marvel of the stonemason’s art, towering 55 m above its base on the rocks. Its light now rums automatically, but still provides vital guidance for mariners.

Ardnamurchan is a world-famous locality for geologists, an example of what is known as a ‘ring-complex’, a circular arrangement of igneous rocks that lay beneath a volcano.

The rocks

There are three sets of overlapping rock rings on Ardnamurchan, of which the last to form, Centre 3, is the most complete. It became famous early in the 20th century because it was the subject of early examples of aerial photography. The ring of hills in the picture is composed of a very coarsely crystalline relative of basalt, called eucrite.

The Ardnamurchan volcano was one of four which developed along what is now the west coast of Highland Scotland about 60 million years ago. Their formation marked the beginning of the opening of the North Atlantic Ocean, which continues to the present day, along the largely submarine the Mid-Atlantic Ridge. Today they form the islands of Mull, Rum and Skye and the peninsula of Ardnamurchan. Northern Skye and much of Mull are built of piled lava flows from a central volcano, and the Isle of Eigg is almost entirely composed of lavas extruded through fissures. Rum and Ardnamurchan are mostly composed of rocks that formed beneath the volcano itself, in a large magma chamber on Rum, and in a complicated sub-surface ring structure on Ardnamurchan.

Cone-sheets of basalt, inclined towards the left, near Mingary Pier, Kilchoan

Structures for which Ardnamurchan is world famous are called cone-sheets. They formed when batches of basalt magma rising from below produced conical fractures, pointing down into the brittle crust of the Earth. The result is a pile of cones of basalt, resembling a stack of ice-cream cones but often separated by layers of pre-existing rock. There are hundreds of them on Ardnamurchan, estimated to have a total thickness of at least 1 km.

Our display

A room devoted to the geology of Ardnamurchan and developed by Lochaber Geopark is part of a building managed by the lighthouse trust and mainly devoted to the history and construction of the light-house. The Trust makes a small charge for visits, including climbing the light-house.

Alan Stevenson’s marvellous granite light-house. The Lighthouse Trust and Lochaber Geopark displays are in the building on the left.

 

Our display includes 15 interpretative panels designed for children, explaining the development of the volcano as seen from a rocket shaped like a light-house….

and ten panels for grown-ups.

There are also displays of local rocks, minerals, including strontianite, from the mines at Strontian, and fossils. Beautiful Jurassic fossils can be seen in the fore-shore west of Kilchoan village but should on no account be collected.

A corner of the Geopark display

A Jurassic ammonite from Kilchoan

A trip to Ardnamurchan Point is a memorable experience, an unforgettable wild and wonderful place. Climb the light-house and understand the world-famous geology on display.