Earth Cache: Observing the Highland Boundary Fault from Conic Hill
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Scotland's tectonics consist of five different regions, which are divided by four geological faults: Moine Thrust, Great Glen Fault, Highland Boundary Fault and the Southern Uplands Fault.
The Highland Boundary Fault traverses Scotland from the west (Isle of Arran) to the east (Stonehaven) and separates the Highlands from the Lowlands. The landscape north of the Highland Boundary Fault is categorized as mountainous and rugged. The region south of the Highland Boundary Fault consists of lowlands and rolling hills.
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The Highland Boundary Fault marks the largest landscape difference of the four major faults found in Scotland. The fault was active during the Caledonian Orogeny, a plate tectonic collision which took place from Mid Ordovician to Mid Devonian periods (520 to 400 million years ago), during the closure of the Iapetus Ocean. The fault allowed the Midland Valley to descend as a major rift by up to 4000 metres and there was subsequently vertical movement. This earlier vertical movement was later replaced by a horizontal shear.
The Earth Cache
Follow West Highland Way from Drymen or Balmaha to N 56° 05.822 W 004° 31.612 (Waypoint WHW). There you have to leave the WHW and crest the last few vertical meters to the top of Conic Hill. From here you have a beautiful view of the small islands in Loch Lomond. They perfectly indicate the line of the fault.
For log permission
Send an e-mail with your answers to the following questions:
- A - Which rock is harder? North or south of the fault?
_ _ _ _ _
- B - What kind of rock can be principally found in the south of the fault?
_ _ _ - _ _ _ - _ _ _ _ _ _ _ _ _ (only the word in the middle - fourth to seventh letter - is needed for the e-mail address)
- C - Where does the name Conic Hill derive from?
1 Quite easy. The hill has a conic shape.
2 Conic is derived from the Gaelic word for moss.
3 A lot of poison hemlock grow on the hill, which produce the poisonous alkaloid conin. That's why the hill was called Conin Hill in former times, but cartographer in the 17th century did a spelling mistake.
- D - From Conic Hill the course of the fault within Loch Lomand is quite obvious. Send me the bearing of the line of islands, that indicate the fault. How many islands can you see?
- E - What altitude does your GPS device show on top of Conic Hill?
- F - Don't forget to mention your GC nick name in your e-mail
- G - optional: Upload a photo of you or your GPS device on top of Conic Hill (see example).
Use the first three answers to find the right e-mail address: AAAAA.BBB.C@googlemail.com (example: west.granit.4@googlemail.com). Please write only GC2FZM3 in the subject heading. If your answers are correct you will receive an auto-reply message immediately (before complaining to me, please check also you SPAM folder).