Far-travelled Pebbles in Your Garden

Look closely in your flower beds, local park or on your allotment and you’ll almost certainly find rounded pebbles of a smooth, fine-grained rock-type known as quartzite. They are actually pretty monotonous-looking objects – brown or slightly reddish in appearance, but intensely hard and sometimes varied by interesting fractures, cracks or mineral veins.

Remarkably, these pebbles originated as sand in ancient seas to the south of Britain, nearly half a billion years ago. By a quarter of a billion years ago, the sand layers had been transformed into squashed, buckled quartzite rock layers in a mountain chain over what is now the Armorican peninsula of northern France. As the mountains eroded away, desert flash floods gradually shunted the pebbles northwards into what is now central England. The rest, as they say, is history!

More details are available via this link or the audio clip.

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