Time-travelling by train – Carlisle to Newcastle part 2

Send us Fan MailWe got as far as Brampton station last time. We have changed bedrock from the red Triassic sandstones of the west to 335 to 310 million year old Carboniferous strata – a repeating mix of layers of sandstone, shale, limestone and coal. A product of different past environments when the tectonic plate we were part of was on the Equator.  Back then the land and sea kept changing places. Shallow coral seas produced the limestones, when sea level fell the environment became brackish coastal muddy lagoons – laying down the shales, which were then covered by sand from large rivers – the sandstones, and in turn they were covered by vegetation and swamps – ultimately decaying and compacting to form coal seams.  That repeating sequence of rocks – initially with more marine deposits like limestone and as we get closer to Newcastle – more land deposits like sand, mud and coal – is the story of the Carboniferous. Not that we will see much of it directly, this rail journey takes us through a landscape who’s shape and sediments owes most to that last glaciation, its melting and the action of rivers and gravity since.