I’ve just enjoyed a wet AND warm week in Scotland. Oh, kayaker’s heaven. It was a case of third time lucky; I finally got some water and experienced a whole array of new-to-me rivers. It was also a chance to encounter the River Roy in its full splendor by paddling from the head of the Glen to Roy Bridge.

There’s something quite special about Glen Roy. The road follows the river, only to come to a sudden termination at the head of the valley. All that lies ahead of you is the catchment divide between the Roy and the Spey, plus a few sheep. The road eventually leaves the trees and the few scattered houses behind and the Glen suddenly opens out into a vista of craggy slopes leading to mountain tops and the river down below. I like to believe that kayakers are the only people who know that this spectacular Glen exists, except that it has one claim to fame….

Parallel Roads, Glen Roy. Photo by Tom Crow.

Glen Roy is renowned for its Parallel Roads. There are three distinctive lines that run across both sides of the valley which are the remains of shorelines from an ice damned lake that filled the valley during the last stadial, the Younger Dryas (Loch Lomond stadial). This cold period lasted a brief 1300 years and terminated around 11,640 years BP*, the start of our current interstadial, the Holocene.

With respect to the geology of the River Roy, the Parallel Roads are less than the blink of an eye. The Roy flows through the Grampian Group and Appin Group, both sediments of Precambrian age (around 750 to 540 million years old) that were deposited in the Iapetus Ocean. These sediments were then metamorphosed during the mountain building of the Caledonian Orogeny which joined England and Wales to Scotland.

The sedimentary layers, metamorphism and consequent schistose fabric (alignment of minerals) within the Grampian Group is the reason for the instability of the geology in the Roy Gorge and the cause of the evolution of the rapids on the river.

*BP means before present and actually equates to 1950, the advent of radiocarbon dating.

PS What is it with Scottish kayaking trips and breaking boats???

Head of the Glen. Photo by Ol Renison.

Wish You Were Here, River Roy. Photo by Simon Knox.

Mamba's days are numbered, Wish You Were Here, River Roy. Photo by Ol Renison.

Escaping Roy Gorge...

Way, way back in June I attended Mark’s South West Sea Kayak Meet. It was one of the few occasions this year when I actually got out in a sea kayak (I’ve been locked in battle with DIY, amongst other things). I had a fantastic weekend – lovely paddling, meeting old friends, making new friends, great talks and the Pig’s Nose Inn was its usual bizarre self (the staff thoroughly embarrassed me in exchange for Birthday cake). I don’t think I’ve ever seen so many paddlers on the sea at one time. Great! P&H were also in attendance, so I got a demo boat fix too.

Spot the kayaker, Hallsands. Photo by Anne Hanson.

Saturday brought with it a foggy paddle south of Hallsands, the highlight being seal TV (they sprawled on the rocks, we watched transfixed). I got to paddle a glittery turquoise Quest LV, which I loved. However, I don’t recommend using a VHF tag containing the word ‘glitter’; it upsets the Coastguard!

Atlantic swell, scattered with sunshine, made Sunday’s paddle from Thurlestone Sands a perfect rockhopping opportunity for those who dared. I braved the swell through Thurlestone arch, or maybe it was just a case of demo boat courage?

Thurlestone arch is composed of Permian breccio-conglomerate*. Although the swell didn’t allow for close inspection, it is composed of pebbles (and even boulders) of local Devonian and Carboniferous rocks that were transported by water. This sedimentary rock was created by flash floods in a desert environment, deposited by a wadi.  The very mixed grain size is the result of the sudden cessation of water velocity and the rapid deposition of sediment.

Comparatively, in environments where water velocity decreases slowly, the deposited sediment will gradually decrease in size with smaller and smaller particles being deposited over time (the opposite is never true as increasing water velocity causes erosion and transportation). This sorting of sediment size can be clearly observed in the geological record and is known as a ‘fining upwards sequence’.

A fining upwards sequence can be used as an important tool known as ‘way-up indicator’. It is entirely possible to view rocks that have been completely overturned by folding; they are simply upside down. When it is present, inverted fining upwards can be used as evidence to prove that this is the case.

Here’s to SWSKM 2010…

* A breccia has angular clasts that have been deposited close to source and a conglomerate has rounded clasts that have been smoothed by transportation. A breccio-conglomerate contains a mixture of angular and rounded clasts.

Demo boat courage, Thurlestone arch. Photo by Anne Hanson.

Breccio-conglomerate, Thurlestone arch (you try taking photos of rocks in swell!)

I’ve finally dusted off the sea kayak; it’s not been out to play since paddling to Lundy back in September. Oh dear. But I feel that I’ve more than made up for it. I have discovered a little corner of home grown paradise. That’s right, I’ve been to the Isles of Scilly….

The bluest blue, north coast of St. Martins. Photo by Mark Rainsley.

The short few days on the Scillies were enough for me to fall in love with those rocks on the edge of the Atlantic. There is an air of tranquil romance about the place; an idyllic hush merges with the deep blue sea and white sands, all sprinkled with the riotous colour of flowers. Being able to dip in and out of the many islands by sea kayak is just the icing on the cake. Even my sea sickness and the very exciting* crossing back to St. Mary’s to catch the ferry didn’t dampen my spirits and my promise to return.

Unlucky for you guys, the Isles of Scilly is yet another granite. All my kayaking appears to be granite themed at the moment. I must diversify!

The Scilly granite is an outcrop of a large batholith that joins all the Devon and Cornwall granites at depth; it’s just a smaller sibling of Land’s End, Bodmin and Dartmoor (but not Lundy). This granite mass is related to the ending of the Variscan Orogeny. The Variscan Orogeny is a mountain building event caused by the collision of Gondwana (S. America, Africa, Antarctica and Australia) and Laurentia (N. America) that occurred during the Carboniferous and created the super-continent Pangaea.

The heat generated from the granite and the movement of hot fluids through fractures and fissures in the country rock  is the root cause of Cornwall being a historically important mining location for tin (cassiterite), copper, lead, zinc and silver. In addition, the degradation (it literally rots in humid conditions) of the granitic feldspar to kaolinite is also important for the extraction of China Clay. China Clay doesn’t just make china, it even goes in toothpaste and makes paper smooth. It also provided the hole-in-the-ground for the Eden Project.

I’m not sure what happened to taking any kayaking photos; I appear to have gone flower crazy. But there are lots more photos here…

*this means big cross swell and white horses breaking over the deck

The Eastern Isles

Tresco Gardens

A room with a view, St Agnes.

Salvaged ship figurehead, Tresco

Tean, I think?

Three geologists were returning, on a train, from fieldwork in Scotland.  As you would imagine they were reviewing their trip, basically talking ’shop’.

They were joined on their table seat by an unsuspecting member of the public, Mr Joe Bloggs. When Joe got up to leave the train, he could no longer contain himself. With more than a hint of worry in his voice, he asked if they were from the MoD. He wanted to know if they had been talking in code!!! The poor man had been sat there the entire journey, terrified that he was eavesdropping upon a conversation of top security.

I was recently talking to an A-Level geology teacher about how the best thing his prospective students can have for studying the subject is a good memory. Like all sciences, geology has a language all of its own.

If I do a quick trawl of my memory, this is what falls out….

hornblende, greenschist, porphyroblast, recumbent folds, allochthonous, pahoehoe, lath, galena, rhyolite, turbidite, dextral, strike-slip, horst and graben, cleavage, groundmass, ophiolite, anticline, psammite, pyroxene, orthorombic, gniess, belemnite, isotropic, ductile and, of course, garnet.

The Ammonite. The public's favourite fossil?

I’ve been exploring again. I spent hours walking the cliffs without seeing a single soul. Blissful. But next time, the kayak will be coming with me…

Now that's what I call a coastal path

Unexplained pigeon loft??? Really, that's the claim.

A huge foreshore of spikey limestone

The smell of gorse...

In the Coast post below, you’ll see a juxtaposition of very obviously different rocks…

Blue Anchor fault, Blue Anchor Bay, Somerset

The photo shows two Triassic rocks of differing age set against each other; the Red Marls and the Penarth Group of layered shales and limestone. Between the two rock groups is a fault. The Red Marls are the ‘foot wall’ and the grey Penarth Group are the ‘hanging wall’, simply because the grey rock is hanging over the red rock.

By looking at the fault it is possible to determine that the Penarth Group has fallen in relation to the Red Marls. This means that this is a normal fault formed during extensional processes. If the Penarth Group had risen, it would be a thrust fault caused by compression.

As faults go, I think this one is rather lovely. Cream teas are also good.

Due to this exciting day of exploration, my garden now contains a fine and very large specimen of pink gypsum (calcium sulphate), aka ‘Apricot Sorbet rock’. Plasterboard has never been so interesting.

Creamy, jammy scone. Kilve, Somerset.

Pink gypsum within the Penarth Group.

There’s so much of it to explore….

I eddied out below Clavey Falls on the Tuolomne and looked at the rock in front of me. “Boundinage”, I exclaimed!

Where did this come from? Why had I been hiding this term in the recesses of my mind, for it suddenly to leap out when I was least expecting it? My memory appears to have a geology locker that I didn’t know existed.

Boudins on the Tuolumne. No scale, tut tut.

Boundins are formed during extension of the rock. In this example the beds of the sediment are orientated vertically and composed of muddy and sandy beds. Because the sandy beds contain more quartz, they are ’strong’ or ‘competent’. So when they are stretched, these beds break apart and form the sausage shape boudins, whilst the muddier beds can quite happily be elastic (fantastic).

We paddled 18 miles of the Tuolumne and that’s a lot of miles of big bouncy grade III and IV. I can happily say that there was a distinct lack of rocks in the river, just how I like it. We were supposed to overnight on the river, but when the shuttle took 3 hours (miles of switch-back dirt tracks and LA stylee ghetto bridges – don’t ask), we didn’t manage to get on until 6pm. With darkness only around the corner, we paddled the first rapid and got off! It turned out to be a good choice; there were no good camping spots for miles after this…

Much respect and gratitude to Mrs R for the provision of the marshmallows. Heather really knows how to make a perfect camping spot even betterer.

Clavey Falls, Tuolumne. Photo by Dave Hodgkinson.

Yours truly on the Tuolumne. Photo by Mark Rainsley.

Kit carnage at the get off. Don't look too closely at the graffiti!

We turned off the deserted road between Somes Bar and Happy Camp. The slow journey up five miles of dirt track commenced (don’t tell the car hire company). This way to Clear Creek!

To the river! Photo by Simon Knox.

Mark said there was a grade V un-inspectable gorge. We all passed, everyone except Simon. Between moments of sunshine and snow, I followed Simon and Mark up the trail to the river, looking at the rocks.

Hmmm, black, sparkly, igneous. Could be pyroxene and olivine (I never was very good at identifying minerals in the field). It’s ultra-basic. That’ll do.

Igneous rocks have a sliding scale of composition, varying from acidic to basic depending on the amount of silica they contain. Volcanic rocks have the same system. This defines the nomenclature, so you have your granite at the acid end and peridotite at the basic end. Therefore, I shall pronounce that Clear Creek flows through peridotite. Although I’m not rightly sure

It doesn’t really matter though, as it was an astoundingly beautiful spot. The trail disappeared off into the woods. I didn’t dare go too far, what with the bears and all. It wasn’t until I got back that I read the notices on how to avoid attacks from mountain lions (aka pumas). They kill their prey by severing the spinal chord at the base of the skull, so never turn your back on the big cat! I like living in li’l ole England sometimes.

Simon and Mark, Clear Creek.

Big cats and bears this way...

What's in a name?

Clear Creek Trail. Photo by Ol Renison.

I have to go back to Yosemite; there’s just no denying it. I want to walk off into the woods, regardless of the bears, mountain lions, poison oak, rattlesnakes…

And I also have to go back for Mono Lake. I can’t believe that I was so close and didn’t go!

Mono Lake is an odd one, a freaky number. The white spires within the lake are tufa. It’s made of calcium carbonate, the same stuff as limestone. The process that forms tufa is essentially the same as cave formations (think stalagtites and flowstone), but not in a cave!

So you have some hard water and the calcium carbonate comes out of solution and becomes a solid, usually through a change in temperature, pressure or through turbulence of the water. This is exactly what happens at home when the kettle goes scaly.

For those interested in some chemistry, it’s this:

Ca(HCO3)2 <=> CaCO3 + H2O + CO2

Calcium bicarbonate to calcium carbonate plus water plus carbon dioxide

Even on the tufa scale, Mono Lake is pretty unusual. The columns have formed where springs enter the lake and they’ve only been exposed due to falling lake levels caused by water abstraction. They should be underwater!

I know A LOT about tufa; I studied it for 4 years. So you can probably understand why I’m upset about not going to Mono Lake and paddling between those white columns.

…don’t know when I’ll be back again. But it will happen, sometime.