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Alum Bay, Isle of Wight

 

 

Alum Bay: Photo By Debbie Lowless

Alum Bay on the Isle of Wight has one of the most spectacular sequences of rock layers, or strata, in Britain. These layers are the remains of mud laid down on ancient sea floors. Over millions of years successive layers of mud hardened into rock, and were lifted out of the sea by movements of the Earth's crust. This layering can then be read like a book, telling the story of the distant past. Comparisons with a book are particularly apt at Alum Bay because crustal distortion has tipped the layers on their sides. If you stand on the beach and look up at the cliffs you will see "volumes" of Earth's history on a shelf in front of you. Let your eye run from right to left and you are travelling forwards through time. Alum Bay can actually show the changes from a world dominated by dinosaurs to the very different world that followed their demise, probably caused by a huge meteorite strike in Central America. Look for the point where a volume of white crumbling chalk stands next to a red volume of clay. The white stripe was laid down in the world of the dinosaurs, while the red stripe was laid down in the world that came after them. Unfortunately the crucial layer showing the actual time of the meteorite strike is missing at Alum Bay. For that you will have to go to Gubbio in Italy, to Tunisia or to the western USA.