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Wednesday, September 25, 2013

Geology Fieldwork in the Scottish Highlands

As a child my favorite issues of National Geographic (like so many families, we had a shelf full of every issue since my parents began a subscription) were the ones that showed the inexorable movement of Earth's crust in the form of flowing Hawaiian volcanoes and the enormous 1964 Easter earthquake in Alaska.  As a college student geology appealed to me because it was like putting together a puzzle with a bunch of the pieces missing and because geologists get to go to some of the most fascinating and beautiful places on the planet.  Although I am no longer working as a geoscientist, I have been able to help organize and participate in some cool trips, most recently to the northwest highlands of Scotland, which even after centuries of study by hundreds of geologists, offer opportunities for new geologic discoveries.

Steve has been studying fractures in the Torridonian, mostly in an area referred to as "The Great Wilderness," for about a decade and this trip was made to confirm several items for a paper he is working on.  I went along as field assistant and photographer.  I was prepared with a field notebook for which I made a cover out of some scraps of leather - not waterproof, but water resistant.

Comparator (on top of notebook) from Ortega, et al, 2006* is for measuring fracture widths

Aside from having extensive and well-exposed outcrops, The Great Wilderness is home to big peaks, including An Teallach and Slioch, and countless inland lochs, of which the largest is Loch Maree.  As the name implies, however, there are no paved roads so sturdy waterproof boots and gaiters are required to navigate through the mostly open, but boggy countryside.

Torridonian sandstone and Eriboll quartzite

Slioch, on the north eastern shore of Loch Maree, offers views of Ben Eighe to the southwest and of Skye and the Hebrides to the west.

Ben Eighe
Ben Eighe and Loch Maree
Atop Slioch
Along the ridge of Slioch

Past Gairloch and Melvaig, where the road becomes a winding single track, you will find the Rua Reidh Lighthouse.  We were greeted with an array of rainbows along the way.

As well as abandoned but scenic old houses.

Once at the lighthouse you may see seals, whales, sea otters, and a variety of sea birds.  You can wander around on the Torridonian sandstone adjacent to the lighthouse.  Notable features include cross-beds, ripple marks, multiple fracture sets, and filled fractures.  You can also walk for miles along the top of the cliff and even make your way down to a protected beach.  In addition to its function as a navigation aid, the lighthouse now operates as a guest house. 

Rua Reidh Lighthouse
Torridonian crossbeds
Small scale ripple marks superimposed on large scale ripple marks

The scenery seems to change as quickly as the weather in Scotland.  With every bend in the road there is something new to delight the eye.

Gruinard Bay

We spent the latter part of our trip farther north, in Rhiconich, at the head of Loch Inchard.  Here is the view to which we awoke the day we planned to hike to the top of Foinaven.

As we prepared to step out of the hotel it became a bit more promising.

It continued to be promising as we hiked towards the base of the mountain.

But no luck.  The closer we got to the mountain, the harder the rain fell and the stronger the winds blew.  My rain jacket, which seemed to work so well in Antarctica, was no match for Scotland.  Cold, soaked to the skin and unable to use my hands and arms, we turned back.  It was a hard decision to make since we had heard that by 2:30 it was supposed to be clear.  Well, the forecast was not quite right.  It didn't clear until 2:40!  By about 3:30 this is what it looked like.

Foinaven and Arkle

With all this hiking I didn't have time for needlework, but the trip reminded me of shawls I knit using yarn purchased years ago from a lady near Loch Torridon.  Funny that I hadn't previously realized that the green is the color of gorse and the purple is the color of heather.

Muir Woods shawl pattern by Rosemary Hill;  highland wool

Shetland Triangle pattern by Evelyn A. Clark**; angora 

*Ortega, O. J., Marrett, R., and Laubach, S. E., 2006, A scale-independent approach to fracture intensity and average fracture spacing: AAPG Bulletin, v. 90, no. 2 (Feb. 2006), 193-208
*In Allen, P. and Budd, A., 2005, Wrap Style, Interweave Press

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