Cold Snap Hits Southern and Eastern England – Time to Salt the Roads
The first really cold weather of winter has arrived. Last night the temperature dropped to well below freezing, when we arrived at the warehouse this morning we found that the pond in yard had completely frozen over, this is the first time it has happened this winter. Although we in the north-west of England have not experienced the snow storms and really cold weather of southern and eastern England it is certainly chilly in the warehouse. Gloves and hats are the order of the day.
The gritting and salting lorries were in action across the country last night, spreading rock salt and grit to help make driving conditions easier. This is the first time these vehicles have been out in force across the UK.
Much of the rock salt that is used on Britain’s roads is mined from Cheshire. The salt and grit that is spread on our roads that originates from Cheshire is approximately 245 million years old. It dates from before the time of the dinosaurs, a time when the Palaeozoic was giving way to the Mesozoic and the Permian period was ending and the Triassic period beginning. The salt deposits were laid down during the late Permian and early Triassic when rising sea levels led to the encroachment of seawater forming large areas of shallow sea and salt marshes. At this time in the Earth’s history, the land that was to become the UK and Europe made up part of a huge land mass called Laurentia, a spur of the super-continent of Pangaea. Britain was much nearer the equator and the shallow seas were surrounded by deserts (hence the sandstone deposits that dominate Cheshire’s geology).
Slowly much of the area covered with sea was evaporated and huge areas of salt lakes and evaporites (minerals deposited from the evaporation of water) were formed. Some were eroded away as they remained on the surface, but other deposits were buried and these rock salt deposits are the source of the grit we use on our roads. Rock salt mining also occurs in Poland and Germany, so you can get an idea of the extent of the shallow seas that formed during this time.