Sunday, 19 November 2017

Lighthouse Path Walk 19 Nov 2017

Took a stroll along the newly repaired Lighthouse path that goes to Rubha nan Gall. Great views over to Morvern, up Loch Sunart and over to Kilchoan. I wanted to have a look at the geology esp since if there had been some digging going on during the path upgrade, then there might be some goodies to see.  Here in pictures is what you can see on the path. Of historic interest, this is the location where Prof Heddle discovered the mineral Tobermorite.

The new gate on the path

A bit further on, there are some neat dykes on the shore at Rubha na Leip:


The smaller of the 2 dykes, about 0.5m across


The larger of the dykes - about 3m in width and showing very pronounced columnar jointing.Both dykes run NW-SE - Classic "Mull Swarm" stuff.

Further along the path there are some interesting amygdales to be seen in the cliff face above the path. Some of the rock here has been recently excavated so is quite fresh. 50p for scale. It was in amygdales that Prof Heddle found Tobermorite, but nothing I saw in the cliff matches the description given in his 19th century paper in Mineralogical Magazine ( link at the end)




Further along the path some very obvious red bole material can be seen - it is all a bit mixed up with the lavas. No nice clear obvious horizons that stretch laterally for any great distance. 


Some of the reddened material that is visible at path level. 50p for scale

Where the vegetation has been cut, there are now great views out to sea. Lighting conditions werent ideal but the pics give you an idea of the views. Rum could be seen in the distance with snow on it.

Looking over to Loch Sunart.

Beinn Hiant 

The view south - Calve Islad Ben Talla and Dun Da Ghaoithe.

The lavas beside the path as well as showing all the classic stuff like red boles, amygdales and other secondary minerals in veins also have some good spheroidal weathering on display. A couple of pics to show this:

Basically all the common features that you see elsewhere in the lava pile of North Mull can be seen beside the path.

The lighthouse at Rubha nan Gall came into view:


The walkway that forms the approach to the lighthouse is made of a red Jurassic sandstone that was quarried just to the north at Bloody Bay. The quarry can be visited from Ardmore Forest but is a bit of a fight with the vegetation. One of the few places in North Mull where the underlying Mesozoic rocks can be seen. The Doirlinn at Calve is another as is the coast below the Guala Dhubh. I think sandstones of similar age can be seen behind the Co-op in Tobermory!

Looking north from the Lighthouse. A little bit further north of here are a couple of exposures of rocks attributed to Blue Lias / Breakish Formation (Lower Jurassic). Limestones and calcareous sandstones - very hard and hackly. I didnt have time on this trip to go further to see these rocks but here are pictures from a few years ago!


The sedimentary rocks north of Rubha nan Gall. You can see the lighthouse in the background

Final thing to note at this location is an obvious dyke running up the hill slope. The white lichen growing on it makes it really obvious. The guys on the CalMac ferry were telling me that from certain angles it looks like smoke from the chimney of the house!

Dyke of the "Mull Swarm" runs up the hill from the house

Final picture of the day is back at the Tobermory end of the path - behind the gate in the garden of the Western Isles Hotel there is an obvious feature in the cliff. Somebody told me a long time ago that there was a fossil tree there. Assuming this is the same thing, looking at it from a distance ( couldnt get closer as the gate is padlocked) it looks a bit like a dyke. Need to do further investigation!

So that was today - loads to see on a great walk on the repaired path. Recommended!

Some links:














1 comment:

gazwarrior said...

Great read and beautifull photography thanks for the great and informative descriptions.