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Deep Time Walk – Knockan Crag
October 18, 2017 @ 11:00 - 13:00£5 – £15
Explore Deep Time as the story of Scotland’s journey across the planet is told through sculpture and interactive exhibits at Knockan Crag.
Unlock the mysteries of the weird landscape in and around Knockan Crag in the North-West Highlands UNESCO Geopark. Here, you can walk right up to and touch the strange, internationally famous geological phenomenon known as the ‘Moine Thrust’. This is the place where dark, billion- year-old crystalline rocks sit astride far younger, pale yellow limestones. Read on to find out why!
Geologists first learned that rocks can move vast distances when continents collide through studying this strange outcrop. We now know that when two land-masses collide (such as India and Asia today), mountains are pushed up. Deep underground, the rocks are buckled, bent, fractured and heated as one continental landmass pushes up against another. Knockan Crag is a window into the roots of an ancient mountain range, and so we can see the results of these chaotic events at the modern-day surface.
Knockan is at the edge of a continental collision that happened over 400 million years ago, pushing up the Caledonian, Appalachian and Norwegian Mountains. The other edge of this mountain-building event is visible further south, in the Scottish borders and southern Galloway. 500 million years ago, the piece of the Earth’s crust we now call England was part of the Avalonian continent, whilst what we now call Scotland was part of the Laurentian continent. The Iapetus Ocean, as wide as the modern-day Atlantic, separated the two. Over 100 million years the ocean gradually closed up and eventually the two continents collided.
Over the past 100 years geologists have used Knockan Crag to help them work this out and now their theories are applied to understanding mountain building and tectonic plates across the world. However, this was far from a straight-forward development of theory, and some of their early ideas were incredibly controversial at the time.