The Calcite Puzzle Traditional Cache
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Difficulty:
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Terrain:
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Size: 
(small)
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The tiny mine you see at this site was established to produce Calcite but we don’t really know why. Please do not explore the mine as it is not a safe area to enter. The cache is a small clip top container with room for several small objects.
Park on the side streets of Menstrie then take a good track up the hill by a series of zig zags eventually leaving the track at a sharp left turn where a smaller track heads up to the right. Follow this then quad tracks to a gate then more feint tracks up to the mouth of the mine. The small horizontal shaft or ‘adit’ was cut into the hillside after several trial shafts elsewhere to follow a vein of the mineral into the hillside. It is only a short passage as the venture was short either because of small quantity or poor quality.
Calcite is composed of Calcium Carbonate and is the main constituent of Limestone & Marble which are widespread throughout the rest of Great Britain but less common in Scotland. Calcite forms from both the chemical precipitation of calcium carbonate and the transformation of shell, coral, and algal debris into the mineral during many years of a process called diagenesis - the gradual change from one form to another. Limestone is also formed as a deposit in caves from the precipitation of calcium carbonate. Marble is a metamorphic rock that forms when limestone is subjected to heat and pressure.
Although none of these rock types are present in the Ochil Hills themselves they are present in the rocks underlying the Forth valley and we are very close to the scarp edge which was formed by the Ochil fault. This geological event gives rise to the marvellous spectacle of the steep hills rising up from the carse below. It was formed when a large area of the earths surface to the south split along a crack line and collapsed nearly 4km downwards leaving the jagged edge of what was then a 4500m scarp edge. Over the period of geological time this then rebuilt by sedimentation to reduce the gap to a mere 400m today. Could this small outcrop of Calcite be a torn off piece of rock from that catastrophic event of the Carboniferous era?
Calcite is valuable for many things nowadays but when this shaft was being dug the main uses were in iron smelting and as a fertiliser to richen acid soil for cultivation. Both require large quantities of material and the first requires a level of purity so it may have been that this seam could not provide for the needs of the developers so it was abandoned as we see it today.
This cache is one of a set of caches exploring the rich heritage of the Glen. Each cache can be visited independently but there are two good walks that take in parts of the set. This cache is on both walks.
A high level walk of 13 km takes in the hills surrounding the glen and is a substantial venture requiring some good navigation on pathless hills above the 500m line. It covers 7 caches of the set.
The caches are:-
GC23M4D – Calcite Puzzle
GC23B65 – Well Sheltered and Watered
GC23KEM – Battlewatch
GC23MED – Making a Loss
GC23M50 – Hanging On
GC23M52 – James Wright of Loss
GC23M4R – Quarterside
Purists may want to add the cache on the summit of Dumyat - Lost Look GCVX01 - placed by Team Incredible to complete the high level traverse.
A lower level walk of 9 km covering 5 caches is on good tracks all the way but still climbs to a height of 300m in places.
GC23M4D – Calcite Puzzle
GC23M4M – Little Jerah
GC23M50 – Hanging On
GC23M52 – James Wright of Loss
GC23M4R - Quarterside
To continue the low level walk from here head East from the mine and pick up a quad track which rejoins the main track into the Glen. For the high level walk break off up the hillside to Myreton Hill just as you rejoin the track.
Well done Craigleaquestors on First to Find - All the high level walk caches are now in place!
Additional Hints
(Decrypt)
Oruvaq n fgbar wvtfnj chmmyr va n penpx ba gur evtug whfg vafvqr gur ragenapr.
Treasures
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