Leaning Water Tower EarthCache
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Located in a small park in Cyrildene. This is a lovely park and is accessible from the top and the bottom. I would suggest using Aida Street access at the top rather.
In this park, the visible outcrops are of a hard iron-rich shale, and it represents a portion of the Witwatersrand Supergroup. This layer is laterally very extensive and dips towards the south. It was given the name Water Tower Slate by early geologists in the Rand area. It is separated from the underlying quartzite layers by a softer shale layer that does not outcrop at all. The Water Tower Slate is magnetic, due to the presence of abundant magnetitie, a magnetic iron oxide. This is historically very important, because it can be traced underground with magnetic sensitive instruments. Its magnetic character allows the accurate mapping, even when buried under younger rocks which generally cover the Witwatersrand Supergroup. The first systematic magnetic investigation was carried out in the Witwatersrand in 1930. As a result of this and other work, the goldfields at Carletonville were discovered. Similar magnetic investigations assisted in the discovery of other goldfields such as the Free State and Evander goldfields which are totally covered beneath younger rocks and would not have been discovered by the traditional gold exploration and prospecting means known until then.
(Acknowledgments: guidebook to Sites of Geological & Mining Interest on the Central Witwatersrand.; Geological Society of South Africa; 1986).
In order to qualify to log this cache, you need to answer the following questions and email the cache owner. Any logs not accompanied by an email will be deleted.
1) Take a photo of you and your GPSr at this spot with the outcrop visible in the background. [Optional]
2) Look at the exposed slates. Try and estimate the angle that this layer is tilted at. If you imagine the horizontal being 0° and the vertical being 90° - estimate the angle.
3) Look at the rock and describe what you see. Any clues to the high iron or magnetic content (check this if you have a traditional compass in your geocaching kit).
4) Why do you think it got the name “Water Tower Slate”. Give you guess/deduction for the origin of the name.
5) What is the difference between slate and shale?
DO CHECK OUT THE NEAQRBY TRADITIONAL CACHE :)
Additional Hints
(Decrypt)
Erzrzore gb fraq lbhe rznvy!