The visible parts are estimated to have cooled underground over 60 years. The Complex is estimated to contain a volume of around 215km 3 of Dolerite in a network of ancient dykes and extensive sill sheets. The sills slid naturally through the local strata, underlying the current (and rather depleted) coalfields and limestone strata. The insertion of magma dykes and the associated large spreading sills came about from crustal extension. Within this landmass, Britain lurked around the tropics and the area in question was under a shallow sea. The Complex came about during the continental manoeuvres building the Pangaean Supercontinent. The “Great Whin Sill Dolerite Complex” formed some 295 million years ago (“before present”, give or take a year or two), at the end of the Carboniferous period and the start of the Permian. (Being stubborn northerners, the locals also apply the term “Sill” to sandstone outcrops, too, like the Firestone Sill and the Grindstone Sill, puzzling many young geologists.) The Little Whin Sill which intruded first, and The Great Whin Sill which is made of several major swarms. Its average thickness is around 30m, and the maximum known thickness is approximately 70m. It also spreads under the North Sea beyond the local coastline. It stretches from the Teesdale area, north to Berwick.
#Vallum hadriani series#
The Whin Sill is a huge underground volcanic block, created in a series of four major subterranean intrusions, or swarms. It’s not simply a single, long ridge as the scenic pictures of the Roman Wall might suggest. The Whin Sill appears in County Durham, Northumberland and Cumbria. Other, more fanciful sources have also arisen.) (By the way, “Whin” is also a word for the harsh, thorny gorse that frequents the area. Most people will have seen photographs of the Wall perching on scenic crags as it winds across northern England from sea to (ahem) shining sea. A rock so hard, its resistance to weathering offered a natural defence line for Roman engineers and their Wall. “Whin”, is northern UK word for a kind of rock considered too tough for shaping and building. Yes, even in Durham and Tyneside our landscape is shaped by volcanic activity! Welcome to the “Great Whin Sill”. Vindolanda) operated for nearly 300 years generations lived and worked in the shadow of the Wall.ĭid it ever occur to the Romans that ancient volcanic activity gave them their line of defence? I doubt it.Īcross the northern parts of the UK, close to my old home city of Newcastle, rises a magnificent volcanic intrusion weathered out into the landscape. The Wall and its associated forts and towns (i.e. One 500-man unit were Moors from northern Africa! How they must have suffered. I’ve stood many times on The Wall, once on a blisteringly icy New Year’s Day wind that froze my nose and ears, and thought about the poor Auxiliary grunts who had to man this wall. Hadrian’s Wall and Crag Lough, © Nilfanion Rights: And the remnants stand today, most prominently on the Great Whin Sill in Northumberland. It was built from Carboniferous sandstone locally quarried and mortared with local lime (some parts were turf wall). The Vallum Hadriani, or the Pict’s Wall, was started in AD 122 and took seven years to build. It might have kept out some of the midges, too.
Once complete, the Wall forts housed cavalry units for swift action against the Picts in times of war, and to put a stop to their cattle rustling (a long term hobby in the North of England that thrived until recent times Armstrongs, Robsons, Dodds, I’m looking at you.) The Wall also protected Britannica against the ongoing clan fighting rampant among the Picts. Therefore, Hadrian and his officers planned a 73 mile (80 Roman Mile) long wall to mark the northernmost reach of the Empire in Britain and keep irritable Picts out of Roman settlements. What had the Romans ever done for them? Meanwhile, tired of the midges and the lack of decent loot in Pictland, the Romans decided to draw a line. Agriculture, roads, towns and forts sprung up and spread north. Suffice it to say he was a man who consolidated, set defences, and established security before considering expansion of the Roman Empire.įar on the northern reach of the Empire, irritable Caledonian tribes (Picts) from Scotland took a real dislike to the Roman occupation of Britannica that lapped against their lands. Publius Aelius Hadrianus Augustus, The Emperor of Rome, inherited a largely developed Empire. We are delighted to present a guest post by Clive:
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