Humberside Geologist No. 15

Humberside Geologist Online

Hull Geological Society field trip to Ravenscar, 10th September 2006

by T Rockett.

Nine members of the Society descended the steep path down the cliff to the beach. The path follows the line of the Peak Fault. Current opinion is that this is the westerly boundary of a north-south trending graben. An easily identifiable layer of rock, the Dogger, has a downthrow of some 90 metres to the east of the fault relative to its position in the west. On the shore the fault divides, and the triangular area between the two faults is called 'Peak Steel'.

The group walked eastwards along the shore on Alum Shale rock. Much of this was covered with huge blocks of rocks seemingly fallen from the cliff above. Fossils seen included numerous Hildoceras bifrons ammonites, Acreolites and Cuspiteuthis tubluaris belemnites and types of plant material. Several fossils were also seen in the blocks of rock including gastropods, bivalves and ammonites.

After returning to the Peak Fault the group looked at the wave-cut platform to the west. Two large blocks of Shap Granite (one over a cubic metre in size) were seen together with some large, smooth basalt boulders and many smaller erratics. Also on the platform the group looked at a 'routeway' from the cliff to the lower shore, constructed at the time of alum production and export.

A steep climb back up the Peak Fault cliff ended an enjoyable day.

T Rockett.

(c) Hull Geological Society 1999 + 2007