Arthur's Seat Earthcache EarthCache

The Cache

How lucky we are to have, in the centre of Edinburgh, a place which encapsulates so much of geological interest in a such small area. We have the evidence of ancient volcanoes, remains of prehistoric fish, and lava flows. There are limestones, coal, plants from bygone forests, corals from former seas, and fossilised beaches, together with the signs of rather more recent glaciers.

That area is the Royal Park of Holyrood.

Volcanoes at the heart of the City of Edinburgh? Yes, but Edinburgh's volcanoes are very ancient, erupting between 350 and 400 million years ago. That is at least 400 times longer than man has existed on the earth, yet less than a tenth of the history of the earth.

Luckily, the Edinburgh volcanoes have been extinct for a very long time and will not erupt again.

The best preserved of these ancient volcanoes is Arthur's Seat. However, erosion over millions of years has dug deep into the core of the volcano and exposed the vents, lava flows and ash falls, which are all today clearly visible. The vents, which carried the lava to the surface, still reach deep into the earth, although today are cold, solidified and completely blocked.

Geologically what remains is a basalt lava plug that choked the neck of a volcano which would have been active around 350 million years ago. The action of glaciations has cut into its heart, making it one of the most accessible exposures of an ancient volcano.

Although only 250m (823 feet) in height, Arthur's Seat is a notable landmark, dominating the city. Known also as the Lion's Head, Arthur's Seat is the highest of a series of peaks which take the form of a crouched lion.

Directions

You can park at N55° 56.760 W003° 09.231 or N55° 57.226 W003° 09.518. I recommend that you come via Let’s Get Radical and climb up from N55° 56.586 W003° 09.975, going this way is the more difficult route, but is worth it, as you will get to see lava balls, and get a better perspective of the volcano.

The Task

To claim this cache, you will have to climb to the top of Arthur’s Seat and answer the following questions.

But before doing so please take note: If you have an internet connection to log your find, then you have an internet connection to send me the required answers! Send your answers BEFORE posting your log. Failing to do this will result in the deletion of your log without notice. You DO NOT have to wait for a reply. If I have an issue with your email I will contact you about it.

Now down to the questions.

1. Arthur's Seat is a volcanic plug, but there has also been glacial erosion that has exposed one side of the plug and left a long slope on the lee side. What is this type of geological feature called?
2. Opposite the trig point is an information pillar, on it are the co-ordinates for the volcano, but they are indeed wrong. What are the printed co-ordinates that are on the pillar and why do you think they may be wrong?
3. Optional: Get a photo of yourself on top of Arthur's Seat and post it with your log. Please no pictures showing the co-ords printed on top of the pillar!