Sunderland's Barrier Reef Earthcache EarthCache
Sunderland's Barrier Reef Earthcache
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This is a short walk from the recommended parking to the Ordnance
Survey trig-point on the Tunstall Hills local nature reserve; along
the line of an ancient barrier reef.
The best place to park is in the nature reserve's official free car park. The entrance is off Leechmere Road travelling west. Because this is dual carriageway, if you are travelling east you need to use the roundabout nearby to turn back to the correct direction.
The rocks of Permian age form the solid geology to the area running between Sunderland and Hartlepool along the coast and also inland along an escarpment that runs southwards from the west of Sunderland and down through Houghton-le-Spring to Hartlepool. The upper rock sequence belongs to the Magnesian Limestone, although at its base is a unit of sandstones known as the ‘Yellow Sands’ which represent the remnants of ancient Saharan-like desert sand dunes.
The Magnesian Limestone rocks were deposited in a relatively shallow landlocked sea, which extended from north east England to Poland. Within the Magnesian Limestone the remains of fossil reefs (often including numerous fossil algae, bivalves, gastropods and bryozoans) which grew on the edge of the sea can be found. Such reef Limestones are exposed at Tunstall Hills and the site has been known for many years for the diverse and superbly preserved fossils present here. Gentle slopes on the Maiden Paps support species-rich Magnesian Limestone including species such as blue moor-grass, common rock-rose, perennial flax and locally uncommon plants such as frog orchid, autumn gentian and purple milk-vetch.
Required Action
To log this cache you must take a photograph of yourself
and/or your GPS unit facing north-east from the trig-point. You must also answer the following questions via my profile and not in your log:
1. When was the Permian age (in millions of years)?
2. What was the name of the landlocked sea associated with Tunstall Hills?
3. Looking North from the trigpoint you come to a small rock outcrop where the fossils may be exposed - what is the height of this particular rock outcrop from the trigpoint to the track immedietly below?
IMPORTANT: Any logs containing the answers will be deleted without prior warning; any logs without photos will also be deleted without any prior warning
Additional Hints
(Decrypt)
Gnxr bayl cubgbtencuf; yrnir bayl sbbgcevagf