Ventnor lies within an area known as The Undercliff. This area of coastline, stretching from Luccombe in the east, to Blackgang in the west, is a soft rock landslide complex. The landslides themselves form a zone some 500m to 750m in width. These are fronted by sea cliffs of variable height, ranging from 10 to 80m in elevation.
The landslides within Ventnor are developed in Lower and Upper Cretaceous rocks. These consist of over 40m of Gault Clay (known locally as ‘Blue Slipper’), underlain by sandstones and ferruginous sands and overlain by massive Cherty sandstones (Upper Greensand) and Chalk. In several small bays along the Undercliff there are accumulations of fine to coarse gravels and cobbles. At Ventnor, the beach is made up of a light, finer sand, with patches of much coarser red-coloured sand. This coarser material has been mainly formed from the sandstones and ferruginous sands in the area. Due to this geological make up, the beaches in the Undercliff are different in appearance and nature to those of Shanklin and Sandown, which lie further up the south-east coast.
Your tasks
To log this cache, you will need to complete the tasks below. Please message us with the info (rather than post it on your log). You can log a find once we have been sent a message. We may delete your log if your answer is way off the mark.
- Go down onto the beach and examine the COARSE red grains on the beach (not the fine sand). What is the average diameter of these larger grains?
- Landslides in the area have caused the greatest change to the coastline in recent years whereas marine erosion at Ventnor has been very slow, particularly over the past 100 years. What can you see along the coastline and can you explain how (these or this?) has helped to prevent coastal erosion?
- As an optional extra, post a picture on your log of yourself and / or your GPSr on the beach at Ventnor.