Showing posts from February, 2018

Visit to Torr na h-Annaid ROMG Contact

The final location I visited a part of my short trip to the Ross of Mull was to Torr na h-Anaid next to Bendoran Cottage near Bunessan. This is another classic locality where sillimanite is found in the metamorphosed Moine rocks close to the contact with the granite. In the Zaniewski paper I mentioned previously there are some interesting features to be seen at this location. It doesnt take long to visit as it close to the road. Last time I was on this actual site was in November 1979 as an undergraduate!

Heres the view from the road (Google Streetview as I didnt take a pic of the hill:
View from the road up to the hill
Torr na h-Annaid is famous for the development of sillimanite near the contact. After searching about for a bit, I found some rock surfaces where it clearly forms "knots"

Sillimanite knots in the Moine schist - ruler for scale
There was also a small vein of pegmatite nearby:
 Vein of pegmatite cutting the schist

And a close up of the same - Quartz, K Feldspar…

Exploring Knockvologan

Final day of the short geologising trip to explore the Ross of Mull Granite. Classic locations, today's was one of the best - Knockvologan and the coast opposite Erraid Island. Bitingly cold wind but beach was deserted. After spending the morning there I went up to Bendoran Cottage to have a look at the other classic ROMG/ Moine contact on the hill behind the cottage. More of that later, but here are some pics of the Knockvologan area with some brief details

(I used the VMSG 2017 Guide. I was on the VMSG field trip last year and Knockvologan was one of the places we visited. However there were a few locations that werent included then so I had a look today)

First stop to look at the distinctive aplite vein running through the granite near the shore

 The aplite vein runs across the rock face

 In close up

The granite is very coarse with large K-feldspar phenocrysts. RM2 facies

The area is famous for the diorite enclaves in the granite. All sorts of interactions and textures to be se…

Exploring Ardalanish

Continuing my visit to the Ross of Mull, todays walk was to Ardalanish - one of my favourite places. First visited here in Nov 1979 as an undergraduate from St Andrews on what was a wet week for field work. I have been back loads of times but what I wanted to do was to check some of the details with a couple of papers. I was interested in looking at the contact of the Moine rocks with the Ross of Mull Granite (ROMG)  - there is a GCR report on this area as well as a very good paper by Zaniewski, Reavy and Harris published in the Scottish Journal of Geology 2006. I had both of those with me for reference. Fun guy to have on a walk eh? :)

Anyway, the weather was great and since a picture tells more than I can,here are some shots of the area:

Still a bit hazy,Ardalanish bay. Moine rocks form the hillocks, Cliffs in the distance are Paleogene basalts near Carsaig Arches

Down on the shore - this is a pic of one of the locations in the Zaniewski paper - Moine rocks on the right, base of the…

Exploring Kilvickeon Beach

Saturday afternoon was spent near Kilvickeon Beach. One of my favourite beaches in Mull, last time I was in that area was with the VMSG field trip last summer where a day was spent looking at the geology near Scoor. Today was just one of those wander about days, taking pictures of things that caught my fancy.Perfect way to end a hectic week!

The beach and the tidal island of Garbh Eilean. Deserted!. There is a rather neat sill in the distance so I went to have a look at it
Garbh Eilean on the way to the sill
The country rock here is Moine metasediments of the Ardalanish Striped and Banded Formation. Some neat pelitic layers with garnets can be found. This was in a huge block that had fallen from above:
The garnets are quite small as you can see
The sill is nearby: The sill (of Palaeocene age) is much younger than the Moine rocks it is intruded into. It stands out really well as it is a distinctive brown colour. The Moine rocks are mainly grey
The top of the sill has a lot of these fra…