What wouldn't I do for a tutorial?
I suppose most people will see this as madness but I feel it is more a question of enthusiasm than madness....
I set off at 2 am Saturday 23rd July, by car, to the roads of southern Germany and Switzerland. The destination? Somewhere in the Alpine region. Why was I driving the 600 km by night starting at 2 am? Well I had to meet some people or more exactly I had to meet the OUGS group who were all there for a 10 day geological field trip in the Alps. The plan was that I would arrive by 8.30 am and that I would go to a field trip that day and the next day and then drive home afterwards.
On the way to Locarno, I had to go through Central Switzerland and arrived there at sunrise. Coming round the corner of the motorway, I was surprised by a very beautiful sight: the Gotthard. The sun was making pink and light dusty shades of orange on its snow top in a background of light blue sky, contrasted by the still sleepy valley in shades of greys and blacks. It was wondrous and I have still this image engraved in my mind as a highlight of my drive through Switzerland.
I eventually arrived in Minusio (close to Locarno) and suddenly realised that I was in a country where I did not speak the language... Fortunately with my Spanish and French I managed to find the right directions to this place (the signposting was not particularly helpful in this part of Switzerland).
I met a few of the OUGS people and off we went in cars to meet yet
more and onto the field trip high up in the mountains.
Road section above Fusio
I felt a little shy at first as I didn't know anyone but only knew Linda Fowler through First Class but this was alleviated by the warm welcome I received from all the group. We drove what seemed to be ages up this mountain and stopped for a natural pause and then carried onto Fusio and above. Hairpin bends and one track roads were our lot and although I am used to them I felt a little sea-sick (probably because I was sitting in the back). The top of the mountain was beautiful. I was suddenly aware that the temperature was no longer the warm temperature of the valley below but one which required jumpers and wind-breakers. Kitted up we started our tour: roadside cuttings up the mountain.We had a close look at gneisses formed from the igneous tonalite, including some country rock xenoliths/inclusions. There were some aplite and tonalite intrusions in some of the gneisses and further up the road we also found some folded aplites and folded biotite crystals.
There were also rootless folds from the pre-Permian basin and some augen gneisses, a very curious lithology displaying some white feldspar spots in a darker-grey matrix. The lot looking as eyes in a rock (hence the augen = eyes in German).
A series of alternate intrusion and screen folding caught my eye as I was surprised by the intricate folding and variation of structure within one outcrop. There were 1st, 2nd and 3rd deformation structures (e.g. hook folds) in this rock.
After a fair walk we ended up at the top of the mountain in the Pennine zone near a dam and here the outcrop was indeed very different: yellowy white and grey flat strata inclined at about 50 deg. These rocks were part of a deformed isoclinal fold and the yellow stone was dolomite marble. There was also some very white calcite marble. The presence of tremolite, a white fibrous Mg-rich rock, suggested the presence of silica at some stage in the formation of these rocks.
We then moved onto another outcrop a little further downhill (over side of mountain), and found some weathered brown garnet crystals in graphitic-mica-calc-schists, including other minerals as porphyroblasts, and kyanite. These were part of an outcrop originating from a Jurassic (Bundnerschiefer) argillaceous sedimentary beds (marls and mudrocks) interbedded with carbonate rocks from deep water. There are foraminifera (Globigerina) in the deep-water muds.
The rest of the day was spent walking back up and then down the mountain
side again and then back to the hotel for shower and dinner. I realised
that my ears were rather sore and so I got a little sunburnt while walking
around, I shall make sure that I don't get my hair cut quite so short before
doing this again... I need natural camouflage for my ears!
The Laghetti Shear Zone
The next day we went up another part of the same mountain but this time to look at the Laghetti Shear Zones. After a very steep climb (crawl!) up the slope we arrived near the top when rain started. So getting wet we carried on climbing to a ductile shear zone area (late Variscan) of great interest. Here were coarse-grained granites (pre-Alpine Permian granitoid plutons) with country rock xenoliths as well as lamprophyre dykes, which show evidence of deformation by the Alpine events but were intruded during the Variscan Orogeny. The effect of the shearing was noted when looking at the fairly round structures of the xenoliths deformed into elongated shapes and veins normally fairly straight being folded into buckled folds. The granite crystals took a rather aligned structure, resembling gneisses but the crystals were only re-shaped by the shear rather than forming distinct lineations in the gneisses. Some dykes were also present and a relative age was established for the rocks in this outcrop.All this geology was paused for our lunch at which point I decided to sit down, as I was so wet it surely would never get me any wetter! It didn't! Rain dripped from my hair, arms, rucksack, trousers..... everywhere and everything was wet! My passport was a very sore sight when I eventually found it at the bottom of the little pocket I have in my geology jacket, which I wore under a waterproof (really???) jacket...
After this rather dull day (weather wise!) we descended back down in the mist and did our first impersonation of Ôgorillas in the mist'! However, by then we were cold and very wet and the prospect of a cup of tea or coffee in a little local tea house in the very lovely village of Fusio, was very welcomed. We all went there and had a lovely tea/coffee and at that point it was time for me to take my leave of our hosts and say farewell to the new friends I had made.
Back to the hotel for a shower and packing and off home at 8 pm on Sunday. My final arrival time was 2 am the next day.
Was it enjoyable? YES
Would I do it again? YES
How far would I go for a tutorial? Well at least 600 km and a round
trip of 1200 km is not considered unrealistic... so I don't yet know how
far I would go for a tutorial.... But I don't mind finding out!
Mainland Europe Group
PS See also My first field trip... with OUGS concerning the same excursion
A more detailed report of this excursion is published in
Open University Geological Society Journal, Spring Edition 2001 Volume 22(1):
Alpine starts and afternoon nappes
OUGS Severnside and South West Branches' excursion to the Western Alps July 2000 - Leader Dr William R Fitches
by Linda Fowler, with contributions from Isa Adams, Philip Clark, Martin & Jenny Elsworth, Ted Smith & Rob Tripp
(Your webmaster)
|
||||||||
|
© OUGS Mainland Europe.
7406 |
Last modified on Tuesday, May 10, 2005 at 10:52