What is the Blue Lias?
Q: What is the Blue Lias?
A: The Blue Lias is a formation of rocks mostly found in south west England and parts of south Wales. It is part of the Jurassic Coast World Heritage Site and is part of the Lias Group.
Q: When was the Blue Lias laid down?
A: The Blue Lias was laid down between 195 and 200 million years ago in late Triassic and early Jurassic times.
Q: What types of rocks make up the Blue Lias?
A: The Blue Lias consists of a sequence of limestone and shale layers.
Q: What is the Blue Lias famous for?
A: The Blue Lias is famous for its fossils, especially ammonites. Remains of a number of dinosaurs and the pterosaur Dimorphodon have also been found.
Q: What causes the alternations of limestone and mudstone in the Blue Lias?
A: Short-term climatic variations, thought to be caused by Milankovitch cycles, cause the alternations of limestone and mudstone in the Blue Lias.
Q: What gives the Blue Lias its blue/grey color?
A: Iron pyrite gives the Blue Lias its blue/grey color.
Q: What does the clay-rich mudstone member in the Blue Lias indicate?
A: The deposition of a clay-rich mudstone member shows that it was laid down in a deeper marine environment.
