Well there’s a big surprise, its raining.
Did I say raining? Of course I meant it’s absolutely heaving it down. The Inuit’s have several expressions for snow it is said. The five of us located here in kindly Gareths sheep enclosure, have several expression for Snowdonia’s more temperate precipitation, like, “its damn well raining”, and “its bloody well raining” or – ” its sodding well raining” etc – with each expression followed by the inevitable “again”. But has that dampened our ardour?… well yes it has a bit, but as soon as the sun has got his hat on and the warming light floods the mountains, the magnificent tableau beckons. It doesn’t make us poets you say? yes you’re quite right – but the grandeur of this landscape has a way of inspiring superlatives. Like the Snowdonia rain. Or More precisely – the Moel Hebog rain, which is a good deal more dramatic. Mere rain doesn’t suffice. Torrent is close, Deluge works, Biblical Flood is bang on. But it could be worse, the natural phenomena that produced these mountains 460 million years ago during the Ordovician Caradoc was not particularly clement. This was not a pleasant place to be. There were basaltic fire fountains, Plinian eruptions, deadly nuees ardentes and dense ash falls that blanketed the region, with more eruptions to cover that, and more again, and so on. This was a Volcanic Island Arc on the edge of the Avalon Terrane, and the paleogeography of Snowdonia placed it about 40 degrees latitude, in the southern hemisphere. North Britain was a long way off, attached to Laurentia, the Iapetus Ocean was closing to the north as the Rheic Ocean opened to the south. The oceanic Iapetus plate was subducting beneath our mini continent, driving the volcanism. The deep waters and calm basins of the early Ordovician and Cambrian were transformed with volcanoes rising from an emergent sea floor, dispersing voluminous quantities of pillows, hyaloclastites and breccias as the volcanic pile slumped and sheared under the amassing basalts. Proximal subariel vents produced deep strata of air fall tuffs and eroded tephra, confusing future student geologists as to their provenance. Beneath even this lay the Pre Cambrian basement of gneisses upon which there was once five to seven kilometers of long since eroded metasediments and other Earth materials. Graptolites, Brachiopods and other primitive biota came and went as each brief volcanic hiatus permitted. The finding of tiny saw blades of Didymograptus having the as much potential excitement in this harsh palaeolandscape as the discovery little Knightia herring in the rich Lagerstatten of Wyomings Eocene Green River Formation. At some disputed stage in the mid to late Ordovician a great magmatIc dome rose beneath the region, so much so that huge volumes of volcanic and sedimentary mega breccia slumped off the rising edifice near its centre and to the
WTF?
east of modern day Llyn Dinas. Vents opened on its periphery and as the pluton expended its melt, it collapsed into a Caldera that rivals Glen Coe, although perhaps not as catastrophically. Nevertheless, a synformal ring system and localised volcanogenic fault structures that appear to be independent of the Caledonides is not just plausible but I believe tangible evidence for the immense structure. Its a good story and I’m sticking to it. Far cleverer blokes than I could ever hope to be have devised its premise and if my project examiners don’t like it they’ll have to take it up with Shackleton and Co – sorry, et al. It all makes for a good yarn, the whole region tells a fascinating and exciting story. While climbing these mountains there are movies playing in my head, of vast Volcanic ranges with not just one or two but numerous Plinian columns rising ten thousand metres with streaked out ash fall miles out into the Ordovician Iapetus, of billowing turbdity currents a mile across emerging from great submarine chasms, entombing trilobites and crinoids. I see the ghosts of strata rising miles above - that must have been and are now scattered about the Irish Sea, Cardigan and Chesire basins, of the great Ice sheets and glaciers of the last 2 million years that cut the cirques, arretes and valleys in great ice cream scoops and linear gouges. On the coast ten miles to the south in Cricieth, there is an unconsolidated cliff of glacial till with its lower strata of poorly sorted rock flour and boulders with slates near the top arranged in a south eastern imbrication which means something about glacial flow and lateral moraines presumably. There are erratics scattered about the beach from the size of a melon to the size of Volkswagen Beetles. I recognise some of them as part of my mountain and others more exotic from who knows how much farther away. I saw all this with Jill, my fab mapping partner, while eating the best Fish and Chips we’ve had for ages. Even skimmed a few stones into the rough sea – and as any student on a field trip knows, skimming requires calm waters, not the onshore wind blown breakers I had to play with. So anyway – back to this rain… Jacinta, Chloe and Laura have to contend with A River Runs Through It, in their tent. Yet they maintain a happy zen like state, smile constantly and remain one of the reasons why this mapping malarkey has been a good experience. And they know a lot about hyaloclastics, and the difference between pillow breccia and basaltic agglomerates. My final report will have more than a mark or two owing to our glamorous and intelligent neighbours.
The touristy stuff.
