The Rhosyfelin "abandoned orthostat" is not alone......
On my recent day wandering about on Rodloga Storskar in the Stockholm Archipelago, I came across quite a range of pseudo-proto-orthostats -- here, there and everywhere, resting on rock platforms and almost all of them off the ground -- supported by pillars, props, wedges, fulcrums and even "railway tracks". (These two large rocks, one weighing about 6 tonnes and the other about 5 tonnes, were obviously destined to be dolmen capstones, because there are many others in the lexicon that look very similar in shape.) It's clear that all of the propped-up boulders in this area were destined for Neolithic monuments, and that they give us further evidence of the extent of Neolithic quarrying in this area. They were clearly being dragged down towards the sea for loading onto rafts when they were abandoned. Somehow or other they just got left behind. Perhaps the builders of the nearest dolmens had already fulfilled their quota of capstones and supporting stones and free-standing monoliths? Perhaps building priorities suddenly changed? Perhaps sudden conflict disrupted a previously stable political alliance between tribes in different parts of Sweden?
Only joking. These and thousands of other large boulders in this landscape of low islands and washed surfaces are glacial erratics -- still in the places where they were dumped, and still resting on the stones jammed beneath them when they were "let down" from glacial transport. Most of the fine material (till and fluvioglacial sands and gravels) has been washed away as this area has gradually emerged from the sea as a result of isostatic uplift. Wave action has played a great part in cleaning up the bedrock surfaces. The total amount of isostatic uplift here is about 125m, and the land is still rising at a rate of 4mm per year. During the Neolithic this area was still deeply submerged beneath the sea.
Not sure if you have seen the boulder (about garage size perhaps larger) about half way down Corner Llain Shelby to the east of Garn Fawr on Mynydd Dinas. It rests on very small stones leaving enough space to see clearly underneath and through to the other side. It is similar to these glacial erratics if that is what it is.
ReplyDeleteTalking of erratics, here's a link to Irish singers, Blarney, Merlin, Methusalah, and Alleged human transport of Rocks.
ReplyDeleteIrish singer Val Doonican, whose death at 888 has just been announced, once knocked the Beatles (also previously known as the Quarrymen), of the Number One Album charts with his partially steam - powered gramophone record entitled "Doonican Rocks, But Gently" in 1968.