Please read the description of how rock can be formed and then answer the questions below
The vast majority of sedimentary rock is created through a simple process, when particles settle to the bottom of a body of water. It could also be formed by wind born deposits or carried by glacial ice. If the particles are mostly sand and grit suspended in the water you get sandstone. If the vast majority of the particles falling are animals or shells of animals you get a limestone. If the particles settling are mainly organic, like wood and plants, you will get coal, infused with oil and gas. Once the rock is formed it can be metamorphosed in two main ways, by pressure, heat or both. If rock is subjected to heat, like volcanic heat, it will melt. This will change the structure of the rock dramatically. If the rock is pressurised, the rock will be transformed in a much less dramatic way. Both will change the properties and look of the rock. Simplistically, sandstone will turn to quartzite, limestone will turn to marble. Rocks of different types have different specific gravities. The rock here has a weight of approximately 2.5 tonnes per cubic metre.
Which type of rock is the rock made of?
Sandstone ; If it is unmetamorphised sandstone it could be grey red or yellow in colour. You will be able to identify many parallel lines which run all the way through the rock, where different seasons or catastrophic events have altered the composition of the deposits for a short time. The rock will be quite durable but feel rough to the touch and small grains will come off when you rub it vigorously.
Basalt; Basalt is a dark igneous rock, and is made up of fine particles, because it cooled slowly after it came out of a volcano. It is unsuitable for buildings since it is very hard and difficult to fashion into blocks for building. Basalt can be very soft if it has cooled quickly because of the many air pockets or very hard if it cooled slowly deep underground .
Marble; This is limestone that has been subjected to intense pressure underground due to tectonic movement. This rock is generally white with different coloured veins running through it. It is a very tough rock and would feel very smooth even after years of exposure to the elements.
Granite; This is an igneous rock and will look a little like concrete, being made up of noticeably different crystals of different coloured minerals. You won’t be able to identify fossils because it forms from the cooling down of molten material. This is very good building material since it has no linear weaknesses.
Limestone; A common building material especially in ancient times due to the decorative look of the rock. This is a white rock which suffers from chemical weathering, as a result of acid rain. This is one of the reasons why the Houses of Parliament are now in need of a lot of maintenance.
Questions; Please read the descriptions of the different processes rocks can go through and answer the questions below
1) Please describe the feel and look of the rock; I know it will be cold and possible wet, concentrate on the detail of what it’s made of, what size and colour the grains are.
2) What type of rock do you think it is?
3) The rock is engraved with a phrase, how many words are in this phrase?
If you feel willing and able please post a photo of yourself, your GPS, or something interesting close to the GZ.
DO NOT INCLUDE A PHOTO OF ANY PART OF THE ROCK, PLEASE.
Thanks for visiting this cache and I hope you enjoyed the detour.