The Story of the

Norber Erratics

The story unfolds on a hillside in Yorkshire

Large boulders of gritstone perch on plinths of limestone

Together they tell a story which has been 16,000 years in the making

Their exact location is here….

North of Austwick in the Yorkshire Dales National Park

The boulders are made of gritstone carried by a glacier

from the floor of Crummack Dale about 3 kms to the north

The hillside was scoured by the ice revealing a

pavement of limestone

..on top of which, as the ice retreated, it

deposited its load of gritstone boulders

For 16,000 years the limestone pavement has slowly weathered, dissolved by mildly

acidic rainwater ….

..except where it has been protected by the gritstone boulders lying on top

Gritstone erratic

Plinth of limestone

Height of the pavement at the end of the Ice Age

Gritstone erratic

Plinth of limestone

Height of the pavement today

Solutional weathering since the Ice Age

How long can their plinths survive?

But …..