War Memorial #1655 ~ Scarborough EarthCache

This EarthCache will take you to the highest point in Scarborough. Here stands a huge war memorial with eleven steps leading up to it. This obelisk, known as People of Scarborough, can be seen on the horizon at a great distance from many parts of Scarborough. At night, it is illuminated. It was unveiled on 26 September 1923, where it commemorated civilians and servicemen who died in the first world war. After the second world war and then again after the Korean war, more names were added. It stands as a great monument to those, willingly or otherwise, who made the ultimate sacrifice in service of their country, as well as those who kept the home fires burning.

From Cloughton, near the sea cliffs:

Now for your geology lesson.

Oxidisation is a process that occurs when oxygen reacts with the material, occurring faster in humid air. It involves a loss of electrons in the material being oxidised. Some elements lose electrons more easily than others, making these elements more susceptible to oxidisation. Many metals, particularly iron, oxidise easily. Oxidisation can often be identified by a rusty-red appearance.

Efflorescence is the result of a process whereby water-soluble salts are moved to the surface of a material due to moisture, usually provided by rain or snow. This movement can happen more easily if the material is porous. This results in salt deposits on the surface that crystalise when the moisture evaporates. It is these salt patches that are called efflorescence. They are usually white and powdery in appearance. The accumulation of efflorescence can hasten in humid environments and in the winter.

Lichen is a composite organism, meaning that it forms by symbiosis of multiple organisms. The mutual symbiosis of lichen is between a fungus and either an algae, cyanobacteria or both. The fungus benefits from this symbiosis because it obtains carbon, a food source, from the other organism(s), that feed themselves through photosynthesis. The algae and/or cyanobacteria benefit because the filaments of the fungi protects them from the environment, as well as gathering moisture and nutrients.

There are three types of weathering: physical, chemical and biological.

Physical weathering often occurs from changes in temperature. Rocks can expand slightly when they are heated and contract slightly when they are cooled, which can cause pieces to break away. Temperature changes can also cause water that collects in the cracks in rock to freeze and thaw repeatedly. Water expands when frozen into ice and contracts when it melts, being the opposite way round to how most substances behave. Nevertheless, the pressure caused by expanding ice can cause further cracks and disintegration of the enclosing rock. Rain and wind can also contribute to physical weathering.

Chemical weathering is the result of chemical reactions occuring with minerals in the rock to transform them into new minerals and soluble salts. Oxidisation is a common example of this. Another is acidic rainwater, which is made acidic by the dissolution of carbon dioxide from the air in the rain. The chemically different substances left behind can be dissolved and washed away by water (such as rain), which ultimately causes the erosion of the rock.

Biological weathering is that which is caused by living organisms. Lichen, algae and bacteria can cause this by producing chemicals that can break down the rock they inhabit, which allows them to get the nutrients they require for survival. Even larger animals - such as piddock shells, which release acid - can contribute to this by boring into rocks, usually for protection. In some cases, tree roots can grow through cracks in rock to find moisture and can ultimately push the rocks apart.
 

There are three rock types: igneous, metamorphic and sedimentary.

Igneous rock is formed through the cooling and solidification of magma, located in the mantle and crust of Earth, or lava.

Granite is a common example of igneous rock, which forms after magma crystalises before reaching Earth’s surface. Granite can be found deep underground in nearly every continent, especially in the continental crust of Earth. It is particularly common in mountainous regions. To our knowledge, Earth is the only planet in our solar system that has granite. Because of the high pressure involved in the formation and the slowness of the cooling process, granite has coarse grain-sized crystals and is very strong. Granite has a melting point of around 1240°C, although this varies. When water is present, however, this can reduce to around 650°C.

Metamorphic rock arises from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to heat and pressure, causing profound physical and/or chemical change.

Slate is an example of metamorphic rock. It is formed under relatively low temperature and pressure. Slate forms from what is originally a fine clay, sometimes with sand or volcanic dust. Slate can be black, grey, red, green, blue or purple. Dark slate typically have their colour because of carbonaceous material or finely divided iron sulfide. Important minerals in slate include flakes of chlorite, small amounts of mica and lens-shaped grains of quartz. Slate is split from quarried blocks, by lightly tapping with a mallet, with a chisel positioned against the edge of a block of slate. The mallet causes cracks that appear in the direction of cleavage, which can then be split into two with the chisel. These slate slabs have a high tensile strength and are smooth and even. This process can be repeated to obtain more pieces.

Sedimentary rock is formed by the deposition and subsequent cementation of material at Earth's surface. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle in place. The particles that form a sedimentary rock by accumulation are called sediment.

Sandstone is a common example of sedimentary rock. It forms over time as fragmented rocks, sand, and similarly-sized minerals deposit. Rocks that are a source of sandstone are weathered by water and wind, causing them to erode and be carried away. They can be continually recycled over millions of years. The grains tend to be smaller as the distance the rock travels increases. The sand sediments often mix with other minerals, such as calcites, feldspars and quartz. The resulting grains are turned into sandstone from the pressure of the sediments above and the water that passes through. The gaps are filled in and cemented together by the mixture of the finer grains and the new mineral growth of natural silica or carbonate.

To log this EarthCache, you must do two things.
The first is to send me, via message centre or email, your answers to the following questions:

1a. How would you describe the colour, texture and general appearance of the obelisk?
1b. What rock is it made from?
1c. Is the rock igneous, sedimentary or metamorphic?

2a. There are some faint areas of red discolouration. Some examples can be found on the south-facing side. What causes this weathering?
2b. Is this weathering physical, chemical or biological?

3a. Look at the horizontal north-east corner. Observe the small whitish/greenish patches. What is this?
3b. Is this weathering physical, chemical or biological?

4a. Look low down on the west-facing side. There is a very prominent white patch that looks like it has oozed down from the horizontal seam in the stone. What causes this?
4b. Is this weathering physical, chemical or biological?

5a. Observe the horizontal corners of the obelisk. How does the texture and colour pattern differ compared to the surrounding surfaces?
5b. Along with your observations for 5a, also note that the corners are rougher. What contributes to this weathering?
5c. Is this weathering physical, chemical or biological?

The second thing to do is to upload a photograph of yourself at GZ. If you don't want yourself in the photograph, you can instead take a photograph of an identifying item, preferably something with your Geocaching name written on it. Either way, the photograph should prove that you were at GZ.
 

Also be warned that there is some misinformation on the internet regarding this obelisk, particularly pertaining to its rock type, so I would advise against relying on internet searches specific to this monument to answer the questions.

Thanks to Wandafree for sharing her geological expertise with me as I was setting these questions.
Congratulations to MGowners for FTF.