Sango bay is located on the north coast of Scotland between Durness village and Smoo cave. There is parking available at Durness tourist information centre and there are public toilets in Durness and at Smoo cave car park to the east. Sango bay is a secluded bay situated below Sango bay caravan site. The bay itself is spectacular with golden sands and plentiful rocky outcrops, the water is exceptionally clear and excellent to swim in providing precautions are taken due to the lack of lifeguards.
Sango bay EarthCache makes use of the exceptional geology of the area as well as the superb views of Sango bay and the facilities of the tourist information centre. The beach and all of the surrounding area stretching to the south west down to Ullapool is part of the North West Highlands Geopark. The rocks of the North West Highlands Geopark are very ancient and record a story of past events, from dramatic mountain building to quietly commonplace erosion, as in Scotland today. The rocks in general run from the north coast in a SSE direction through the Geopark towards Ullapool and further south, to the Isle of Skye and beyond.
Sango bay is made up of rocks from the moine thrust belt, approximately 1000 million year old rocks. Overall moine rocks can be found on the east side of the geopark; they were originally shallow water sediments deposited further away to the east, sediment later became sandstones and mudstones- grey in colour as the minerals that held them together were not oxides of iron. These sedimentary rocks were then involved in mountain building and were therefore metamorphosed to a rock called schist, which is formed at lower temperatures and pressures than a gneiss. A silvery mineral called mica grew during the metamorphism, which can often be seen glistening on the wet rock. The Moine rocks were first metamorphosed as long ago as 820 million years ago and steadily moved westward starting from just over 430 million years ago.
The layering that is seen in the Moine rocks is often the original bedding of the sedimentary rock, the pressures and temperatures never having got high enough to destroy this layering by new crystal growth. The layering is generally fairly flat lying just above the low angle major thrust fault called the Moine Thrust. Further to the east outside the geopark area, the layering becomes much steeper as it has been involved in large-scale folding here. These rocks to the east also suffered greater pressures and temperatures during the metamorphism and have undergone a greater change during metamorphism.
To log this EarthCache please email or message me the answers to the following questions.
Looking west over Sango bay from the provided co-ordinates you should be able to see several rocky outcrops, each of these outcrops appears to be tilted so that the rocks are lying diagonally instead of horizontally. Estimate the angle that these rocks are dipping at.
Using the same outcrops estimate what direction they are striking in. To do this look at the direction they are dipping in, and take the directions that are perpendicular. For example a set of rocks dipping north would be striking East-West.
Then walk back across the tourist information centre carpark to a collection of rocks around a compass. Using the compass on the ground and the labels for the rocks describe the rock that is to the west and state its name. Also identify the oldest rock, giving a description, its name and its direction according to the compass.
Finally on the label for the Lewisian gneiss there is a word in brackets, state the word and explain what it might mean in the context of the rocks of the north-west highlands.
You can include a picture of yourself and your GPS looking over Sango bay if you want to.
Please do not include any answers in your logs.