I’m standing listening to the seaweed popping in the early morning sun on the shore near Lochranza on the Isle of Arran. Oystercatchers chirrup and peep, striding through the shallows. The sliver of beach is peppered with oval-round granite pebbles, mixed with sandstones and schists – the formation tale of this part of the world scattered underfoot.
Standing on a shore such as this I’m both reminded of the past and engaged with the present at one and the same moment – a glimpse of deep time held in the palm of my hand; pebbles offering tangible links to a long-distant past. Millions of years old, worn away from the moment of their conception, altered beyond their origins by crystal and mineral growth, heat, pressure and above all, time.
Stack up the pebbles on the beach and you have a succession of ages represented – Precambrian through to Triassic, Permian to the Paleogene. With it comes the palette that helps paint the island – silver grey granite, jet black glassy pitchstone, bright New Red Sandstone, and butter yellow Triassic. I find an unusual piece of orange-red igneous rock, fine-grained and interspersed with feldspar crystals – possibly iron-washed in surrounding sediments before being smoothed by the tumbling sea millennia later.
A hand-lens varies colour still further, finding intricate details in crystal refraction, half-rainbows and mica-shot deep silver. Miniature versions of the valleys and hills pattern the pebbles around the bay; patterns which replicate themselves in the northern slopes when you raise your head.
I love the ‘extended vision’ geology can give you. Not just by looking inward at ever decreasing intricate details of crystals and sand grains, but looking outward, too. To look beyond what is in front of you in the landscape and find an imprint of the past – to ‘see’ another landscape high above the outlines that are currently there, drawing invisible lines out across the sky.
The Arran granite, for example, which forms the mountains in the northern half of the island, started out as a huge intrusion around 5-6 km below the surface. After 60 million years of erosion the granite now forms the skyline, and is still being eroded away to this day. At the time of its inception, when as a molten mass it rose up beneath the Earth’s surface to form its gigantic bubble, the land that is now Scotland was part of the landmass including North America. The surface would have been a desert landscape, underpinned by layers and layers of sedimentary rocks. The igneous, granitic bubble represents part of the beginnings of the Atlantic Ocean, the stretching, thinning and breaking of the crust; the time of the volcanoes along Scotland’s west coast.
Follow these invisible lines in the landscape, imagine a different picture; at times I try projecting it into the future too. Landscapes, however solid they may appear, are completely transient. Parts of Scotland have been swamp, ocean floor, desert, rainforest, Himalayan mountain landscape, and may well be once again. In geological terms our lifetimes are pinpricks, the land we walk on and build on is part of an ever fluid, dynamic system. The lines and outlines we see now will never be the same again, however slowly the changes occur to our eyes.
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