This EarthCache takes you to the entrance to the cemetery in Strathaven. More specifically the EarthCache relates to the stone pillars forming the gateway. Please be respectful to the location.
The stone which forms the gateway is sandstone. Sandstone is a sedimentary rock, formed by the accumulation of sand grains, which over time builds up layers, and eventually rock is formed. Now the sand grains can be laid down by water, or by wind action in a desert. In this case they are the latter, abs are likely from one of the sandstone quarries just to the north of Dumfries at Locharbriggs. This type of sandstone was deposited in the Permian period, when the South of Scotland was covered by a desert.
There are lots of EarthCaches about sandstone, but we are here to look at a feature specific, which is in the sandstone. The specific feature we are going to look at are known as Reduction Spots.
You will notice the colour of the sandstone, it is an orangy red, this occurs because of the iron oxide in the grains of sand making up the stone,the Reduction Spots are the obvious spotty features you can see. You will be asking why are they here? Now the Reduction Spots are not a result of the initial deposition of the sandstone, they arise from later events. However, when the sandstone is deposited, thete might be impurities such as different minerals, different grains or organic materials. The orangy red colour in the sandstone is due to oxidisation of the iron oxide, though the impurities cause a reduced amount of iron oxide, which is further depleted by the action of water leaching out what iron oxide there is, hence why there are spots present.
At times Reduction Halos can be present around the Reduction Spots, these appear as a distinct reddy brown line around the spots, and are also known as Rims. They represent the distinct boundary between the iron oxide rich stone, and the depleted iron oxide area of the Reduction Spots.
This being an earthcache, in order to log it, I ask that you answer some questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
1. Please describe the shape of the Reduction Spots.
2. What is the general colour of the Reduction Spots? Why do you think that the specific colour is present?
3. Is thete any evidence of Reduction Halos?