BBC Christmas Lecture series to reveal secrets of Norfolk's beaches
- Credit: Paul Wilkinson Photography
Norfolk's beaches are one of the county's biggest drawcards, but visitors rarely stop to think about the origin of the shoreline beneath their feet.
Now an Imperial College London professor is about to lift the lid on the backstory of Norfolk's beaches, and shed light on the mystery of why some are covered with sand and others with pebbles.
Professor Chris Jackson will put our beaches under the microscope in a Royal Institution Christmas Lecture to air on BBC4 on December 28.
Prof Jackson said Norfolk's beaches were literally set in stone by processes occurring hundreds of millions of years ago as the UK drifted northwards, from low to high latitudes, on top of a giant tectonic plate.
He said: "Large parts of Norfolk’s cliffs are made of the easily eroded chalk rock which originally formed on the seafloor as lime mud around 90 million year ago.
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"As the layers of lime mud built up and the seafloor subsided, the lime mud turned to chalk, before being uplifted from deep within the Earth to be exposed as the now-famous chalk cliffs.
"Natural erosion by rain, wind, and waves means this soft rock breaks down and dissolves or turns to mud rather than to sand, gradually being washed away.”
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However, trapped within the chalk are flint-like pebbles that are much harder to erode and transport.
Prof Jackson added: “Some rocks, like sandstone and mudstone, are easily eroded and break-down due to the action of waves, forming sandy beaches.
"Other rock types, like chert - a type of flint-like, silica-rich rock found within softer rocks like chalk - do not break down so readily.
"They can withstand intense wave action, although they become very round to form the large pebbles."
Prof Jackson will also explain the impact of human activity on the environment including increased storm activity due to global warming, which is eroding our coastline at a faster rate.
Another factor in this are groynes which can be seen on many Norfolk beaches.
Prof Jackson said: “The groynes serve a specific purpose, but they are unnatural features that try, and often fail, to stop a natural process."
The episode, titled Engine Earth, will be one of three Christmas Lectures and will be broadcast at 8pm.