Cromer Shoal Chalk Beds

Published: Monday 19th Mar 2018

Written by: Georgia Dawson

Ever wondered what lies beneath the waters of the North Norfolk Coast?

The amazing Cromer Shoal Chalk Beds lie so close to the coast and can be partially uncovered during low tide. 

Where did it come from?The chalk under the shore is the result of millions of years of turning plankton fragments into limescale rock, which now reaches up to 460 metres thick. Around 100 million years ago, when the world was a very different place, the production of this limescale rock began. The Cretaceous period spanned across 79 million years; from the end of the Jurassic Period 145 million years ago to the beginning of the Paleogene Period 66 million years ago. During this period, the oxygen-rich atmosphere introduced some amazing species to the world. Where the UK is now lied warm, tropical waters and within this sea were lots and lots of floating algae. The carbon resulted in the algae shedding tiny plates that built up over a long, long time to create chalk. 

What animals and plants live amongst the reef?The incredible Chalk Reef is home to a large variety of animals and plants, including...

  • Little cuttlefish - These are tiny animals, the size of a bee and they eject a blob of black ink as a display of threat.
  • Plumose anemone - Absorbing water to inflate themselves and with around 300 tentacles, the tallest anemones in the UK are traps for animals and food particles.
  • Small spider crabs - These crabs decorate themselves with plants and other bits and bobs to act as camouflage. 
  • Sea toads - Masters of camouflage, sea toads cleverly blend themselves into their surroundings using animals and plants. 
  • Lesser weever fish - These sneaky fish hide themselves under the sand, allowing them to quickly dart out and catch their prey, as well as hide from any local predators. If scared or startled, they raise their poisonous dorsal fin while dashing across the sand.

Where is the Chalk Reef?The Chalk Reef stretches from Cley to Trimingam, covering an area of 321km². 

  1. Cley - Marking the beginning of the Chalk Reef, it appears from under a thick layer of clay. Because of its harder surface, the chalk is more habitable than the clay.
  2. Weybourne - Unused ammunition from World War I and II was left on the seabed of Weybourne and can still be found today. 
  3. Sheringham - The most jagged, uneven chalk begins North of Sheringham Park. Off the centre of Sheringham lies the heart of the reef, with dramatic and amazing features that are quite extraordinary. 
  4. Beeston Regis - At this point, the amazing features of the Chalk Reef seen in Sheringham get a bit smaller. However, the amount of wildlife is still enormous and bustling.
  5. West Runton - The Chalk Reef holds some amazing isolated rocks here at West Runton, some as big as a bus. Simply breath-taking!
  6. East Runton - Some beautiful seaweed can be seen here at East Runton in vibrant red and vivid green.
  7. Cromer - Have a stroll along the Cromer Pier as it takes you above the amazing Chalk Reef. The legs of the Cromer Pier have created an artificial reef, however it leads to the Chalk Reef.
  8. Trimingham - Marking the end of the Chalk Reef, at low tide the vibrant white chalk can be seen. The soft chalk here begins to be covered by the hard clay.

The Cromer Shoal Chalk Beds became a Marine Conservation Zone in January 2016. This means that the particular parts of the reef are protected and regulators will step in to help manage the marine activities where necessary.

For more information about the amazing Cromer Shoal Chalk Beds, the history and the vast range of beautiful creatures which have made the reef their home, please visit the Norfolk Wildlife Trust website. 

Georgia Dawson
Georgia Dawson



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