Are there dinosaurs on the Isle of Man?

The Isle of Man has a long and turbulent geological history which started almost half a billion years ago.  Rocks from different ages are found on the Island including the Ordovician and Carboniferous periods but there is no record of the Jurassic or Cretaceous when dinosaurs were around.  The reason is that parts of the rock record have been removed from the Isle of Man.

The Island as we know it today has been affected by a number of tectonic events where the earth’s plates have moved up and down many kilometres.  One of these events occurred around 60 million years (My) ago when the North Atlantic Ocean was formed.  The continental crust at the edge of the new ocean was uplifted by around 2km, including what is now the Irish Sea to form a plateau reminiscent of present day Norway.  Over time this plateau was eroded by rivers so its height was reduced – in places back to sea level.  Regions with harder rocks were left behind as mountains, including much of northern Britain.  Interestingly enough, the reason the rocks of the Isle of Man, Cumbria and Scotland are resistant to erosion is because they belong to a much older mountain belt stretching from Norway to North America.

Although the rivers which eroded the plateau are long gone, the Manx glens are remnants.  The main effect of the rivers was to remove most of the Cretaceous and Jurassic rocks in the Irish Sea region, and with them any traces of dinosaurs.  Further erosion occurred during the Ice Age.  When the ice withdrew, the Irish Sea and the Isle of Man were left behind, more or less in their present form.  There are a few layers of Jurassic rocks still preserved below the sea to the east of the Isle of Man but we will never know if they contain dinosaur bones or footprints.

Back on the Isle of Man there are other types of fossils and traces of life present in Manx rocks. Many of the fossils are remains of marine creatures which show that the rocks were formed beneath the sea. For example, in certain places the Castletown limestone is crammed full of shells from the Carboniferous period (see photograph). The much older Manx slate (Ordovician) contains very few real fossils but lots of evidence of live in the form of burrows and trails formed by worms and arthropods. In contrast, the Peel sandstone developed in a desert probably around 400 million years (My) ago, during the Devonian period. Nonetheless, there are even traces of life here including the remains of plant roots and crab burrows. Finally, the giant deer in the Manx Museum is a much more recent fossil from the Ice Age.