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.

I’ve just returned from a paddling trip to California. Although I didn’t have a burning desire to the visit the USA, I’ve now realised that those Americans have A LOT of space between their borders. The landscape is beautiful; the wilderness and the wildlife gave me a warm cosy feeling inside.

Sentinel Rock, elevation 7038ft

Although we didn’t paddle the Merced, we ‘allowed’ ourselves a day of tourism at Yosemite National Park. I admit that I’ve been lucky enough to travel to some pretty astounding places in my time, but Yosemite absolutely blew me away. I’ve never been anywhere remotely like it. The rocks literally tower from the ends of your toes! This was more than sufficient for me to ignore the multitudes of early season tourists that were crawling the surface of the ‘easy access’ parts of the park.

Yosemite is another bastion of our old friend, the granite. This spectacular landscape has formed over millions of years. The granite plutons cooled at depth and were gradually unroofed to the surface through processes of erosion. They rose to the heavens during the formation of the Sierra Nevada mountains and v-shaped valleys were eroded by the action of water. Glaciation has scoured the valleys further, grinding the rock and leaving hanging valleys high up within the peaks. A lake filled the valley and the sediments left behind have flattened the valley floor.

Today, the headwaters of the Merced river are continuing to modify the landscape. The granite appears striped by the trails of water running down it. Freeze-thaw action is levering off giant slabs of granite along the exfoliation joints. Yosemite continues to evolve.

Nevada Falls, 594ft

Exfoliation joints

Top of Nevada Falls, elevation 5910ft. Photo by Ol Renison.

Liberty Cap, elevation 7076ft. Photo by Ol Renison.

It's just a squirrel, man!

I came across this whilst looking for information on Mary Anning (1799 – 1847), a Lyme Regis fossil hunter who is, apparently, the cause of the infamous lines “she sells sea shells by the sea shore.”

The article discusses survey geologists Eileen Guppy and Eileen Hendriks. I was left quite stunned when I read this:

“both were unmarried as, officially, female survey officers had to resign on marriage up until 1975.”

In my world, 1975 doesn’t seem all that long ago. Being female and apparently finding pleasure in areas that society deem to be ‘male’ (science, geology, kayaking…get the picture?), I was horrified to discover that my life could have been very different if I had been born a few decades earlier. Or maybe I’m just naive.

Thankfully my world hasn’t been adversely affected by inequality. Well apart from my gripe about the lack of support for female academics who wish to have children. But this isn’t the place to go into that one!

These links made for further interesting reading…