geology raised beaches
BackGeology Raised Beaches
The geology of Gibraltar holds fascinating surprises, like the ancient beach levels found high above current sea levels. Here we show you one of these located at Farringdon’s Battery, 160m above sea level, where fossil sands and wave-eroded boulders are evident.
Others have been found at even higher altitudes such as at Martin’s Cave (180m) and Goat’s Hair Twin Caves (210m).
But how did this happen? How did those beach levels get up there?
The current topography of Gibraltar is the product of two factors – tectonic movements and sea level fluctuations. The Rock of Gibraltar was not always as high as it is today (426m) and sea levels have oscillated since the beginning of the Pleistocene due to glaciations.
Starting around five million years ago, spanning the Pliocene and Pleistocene eras, the Rock has been gradually increasing in height. Geological studies show that from 200 thousand years ago to the present day, the average elevation of the Rock has been 0.05 ± 0.01mm per year and, with a previously higher yearly average of 0.33 ± 0.05mm.
This means that areas nowadays elevated high on the Rock were at sea level thousands of years ago, which explains the origin of those ancient beach levels which we now find in such unexpected areas of Gibraltar.
Published: March 24, 2020
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