Friday, 31 May 2013

Climbing, walking and running Scotland's geology

I'm very aware that when teaching about volcanoes, earthquakes or glaciation, pupils can find it difficult to comprehend the significant time scales involved. It's not surprising when you consider their previous experience of historical time scales revolves around 1066, the Roman Empire and a chap who was pretty good at turning mineral water into a particular type of alcoholic tipple 2000 years ago.

Geological holiday discoveries in your pocket.

But how to learn about geology and the vast timescales without doing a degree? Most of my geological knowledge has been acquired from books, individuals such as Dr John Stevenson during climbing and volcano related trips, and the British Geological Survey's Igeology Android and Ipad app. The app is free to download and provides you with an interactive geological map layered over an OS map at various scales down to 1:50,000. At the touch of a screen you can investigate what the bright array of coloured swirls and blobs symbolise. The terminology can be a little technical at times, but it provides you with rock type and estimated age amongst other things.

A half term week spent climbing and walking through a few prized spots in Scotland shows the diversity of rock that can be encountered and the knowledge available for those with an enquiring mind and a smartphone.

Starting old: the rocks of Dunkeld.

Our first stop on a sunny Saturday was at Dunkeld crag, or Craig a Barnes, a few miles south of Pitlochry and a very handy crag for a quick climb whilst heading north on the A9.

Craig a Barnes local geology. Image from IGeology Android app, British Geological Survey .

The rock was a delight to climb, although a little slippery in places and protection for the nuts and cams took a while to find at times. The Scottish rock climbs guide identified the dark grey, sparkly rock as schist but it was the age of the rocks that took me by surprise. They date from the Neoproterzoic era and are the remnants of sediments that have been compressed and heated as continents collided between 518 and 650 million years ago. Geovertical's blog post on Dunkeld has a good deal more information outlining the geology of Dunkeld and its characteristics.

Cairngorm granite

Moving further north we traveled through increasingly mountainous terrain to arrive in the arena of large whaleback mountains, glaciated valleys and volcanic rocks: the Cairngroms. We camped in Glen Feshie, a quiet wee valley on the edge of the Cairngorm massif and headed up towards Sgor Gaoith with its gentle Eastern slopes standing in contrast with the craggy, plucked and weathered West facing granite crags. The area is a super example of Scotland's volcanic history; the course and multi-coloured grain granite and rolling plateau was formed between 417-443 million years ago as continent slammed into continent during the Caledonian Orogeny.

Looking down into Loch Einich from Sgoran Dubh Mor. Glaciation for all to see! Photo: Alasdair Monteith

A snapshot of the geology of the Cairngorm plateau. Image from IGeology Android app, British Geological Survey .


The Cromdale Hills

Monday was a windy and unappealing day to be out on the hill, but I was keen to explore the Cromdale hills, an area I knew little about apart from in passing along the Tomintoul road. The area reminded me of the smooth slopes and depressions of the Trough of Bowland in Lancashire. The quartzite that covers the hills, a metamorphic rock, can be seen in the photo below and formed around 545-1000 million years as part of the Dalradian group of rocks. The trip was a reminder that it is not just Cairngorm granite that dominates these hills.

Quarzite block on the the summit of Sgor Gaoithe, Cromdale Hills. Useful as a windblock against 45mph winds. Photo: Alasdair Monteith
Quartzites from the Cromdale hills. Image from IGeology Android app, British Geological Survey .

Cummingstoun sandstone

Our last little climbing adventure took us to the sandstone cliff of Cummingstoun on the Moray coastline, an area I have been climbing at for over 15 years. The 'Costa del Moray' often provides a haven from the cold, wind and rain that regularly visits the Cairngorms and Highlands. The rock is 'generally' stable, with a variety of pockets, cracks and slopers ideal for climbing, a by product of erosion and weathering from the sea and local climate.

Cummingstoun... 2003 style. The weathered pockets in the foreground and the crack lines on the far wall provide excellent features for climbing. Photo: Rory Fraser Mackenzie.

The sandstones of Cummingston represent the youngest rocks encountered on our short journey, remnants of an ancient sand dune system that developed during the Triassic period. If you know where to look, fossils clues from the dinosaurs which roamed the ground 250 million years ago can still be found, a time when the area was more akin to a hot desert than a cool, windy Scottish coast. More recently, as the glaciers and ice caps of the last ice age melted, the coast rebounded from the weight of the ice resulting in impressive wave cut features scarring the cliffs several metres high.

The Moray coast: here be dinosaurs.... Image from IGeology Android app, British Geological Survey .

All in all a very enjoyable trip which highlights the range of rocks and the varied physical geography of Scotland. Having access to information on the environment around you is incredibly useful (when you can get 3G coverage, still a rarity in some parts of the UK) and something I have used when teaching and on fieldwork to demonstrate to young people the range of rocks and age of the UK. Hopefully, it encourages them to investigate and ask questions about the land and environment beneath their feet.