An EarthCache which requires you to visit the location given, make some observations and answer some questions.
Please feel free to message or email the answers to me at the same time as logging your find.
There is plenty of parking on the adjacent road and the cache location is accessible by wheelchair or prams.
The Devonian is a geologic period and system of the Paleozoic, spanning 60 million years from the end of the Silurian, 416 million years ago (Mya), to the beginning of the Carboniferous, 359 Mya. It is named after Devon, England, where rocks from this period were first studied.
The Old Red Sandstone consists of bright red mudstones, siltstones and sandstones, together with some conglomerates and green sandstones.
The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the north eastern seaboard of North America. It also extends northwards into Greenland and Svalbard. In Britain it is a sequence of rock strata which is of considerable importance to early palaeontology. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain.
Old Red Sandstone is a thick sequence of Devonian rocks which formed from around 416 million to 359 million years ago. The rocks are continental rather than marine in origin and occur in north Western Europe, Scandinavia, Greenland, and north eastern Canada. Continental rocks were formed inland in lakes and rivers where marine sandstones were laid down in river deltas opening into seas or oceans.
Deposits of Old Red Sandstone have been extensively studied in Great Britain, where local and regional stage names have been applied. The rocks were deposited in structural basins between the ranges of the Caledonian Mountains, which were also formed during the Devonian Period when a section of north Western Europe collided with a landmass made up of parts of present-day North America and Greenland. Thick deposits of sand and mud, 11,000 metres (36,000 feet) deep and often stained red by oxidized iron minerals were present. This slowly accumulated in these sinking basins. The sediments are poorly sorted and quite variable; cross-bedded sandstones, mud-cracked siltstone and shale, and raindrop impressions all occur. Most of the deposits are of a similar colour and construction because of the slow consistent way in which they were deposited. This can be evidenced by the similar colour even though the grain size can be quite varied. The sandstones are red at this location but can be other colours. Plant and animal fossils occur in these deposits; the fossil fauna is characterized by primitive, often armoured fishes.
At this location I wish you to observe the sandstone cliff inland from the concrete path it is very impressive. You might need to leave the path but there are several places where this can be done safely, however you might be able to get what you need from the path since it passes very close the the path at several points,
I’d like you to get close to the rock face and make some observations to answer the questions below.
You may need to read the information above to help.
- Please describe the features of the red sandstone. Please concentrate on the structure of the rock. For example is it crumbly? Is the colour constant throughout? Are the grains all the same size?
- Do you think this rock face was deposited in a consistent way? Please explain your reasoning for your answer.
- Please indicate the height of the cliff face at this location.
If you feel willing and able please include a photo of your visit.
Thanks for visiting the area I hope you feel it was worthwhile.
You are invited to send your answers and log your find simultaneously.
treboR