Sitting in the estuary of the River Dee which divides England and Wales, the are a group of islands which are collectively known as Hilbre Islands. They are Hilbre - Middle Eye - and Little Eye.
These islands are accessible on foot for approximately 6 hours a day during low water. The walk is between 4 and 5 miles in total for the return jouney. For information regarding this please see the various websites or noticeboards at West Kirby. DO NOT attempt to cross before reading the various information. There is a distinct route which must be followed and tide times to be adhered to.
A few facts about Hilbre :-
1. Hilbre Island itself measures about eleven acres, the Middle Eye, about three acres, and Little Eye bring the smallest is just about half an acre.
2.The deposits forming the land were laid down in a vast desert more than 200 million years ago.
3. Hilbre island derived its name after the Medieval Chapel which was built on the island dedicated to St Hildeburgh. The chapel has now long gone.
4. There is an old lighthouse on the island which was constructed in 1927.
5. The islands were sold to Hoylake Council in 1945 for just £2500.
6. Hilbre was inhabited until 2012 when the last person left the island. Rangers do however visit the island on a regular basis.
THE SCIENCE LESSON
- FOLDS - Deformation of rock involves changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering.
-FAULTS-
There are several different kinds of faults. These faults are named according to the type of stress that acts on the rock and by the nature of the movement of the rock blocks either side of the fault plane. Normal faults occur when tensional forces act in opposite directions and cause one slab of the rock to be displaced up and the other slab down. To assist your understanding and for some very good diagrams, reference may be made to http://www.physicalgeography.net/fundamentals/10l.html
There are many geological features on the islands to be explored and this EarthCache features just one of them. Permission has been granted to me by the landowners for the EarthCache.
In order to log this EarthCache please answers the following questions :-
1. If you look at the vertical rock formation, please state the various colours of stone ?
2. What type of stone is this ?
3. As you look at the feature note that there are two distinct colours, if you follow the line of the lighter colour what happens to it ?
4. What do you think caused the feature in Q3 ?
5. Do you think that this feature is a fold or a fault ?
6. How high from the ground level is the left hand side of the line of the fold/fault ?
7. if you would like to add to your answers by sending a photo, that would be nice. Please DO NOT POST IMAGES on the cache page that show the feature.
Please submit your answers via the MESSAGE system which allows a photo to be attached. Any photos containing information about the EarthCache posted on the page will be deleted. Thank You.