This is an accessible EarthCache that will take you to the Cenotaph in Liverpool.
Here you will undertake a geology lesson as you visit this memorial.
As this is an EarthCache you need to send me your answers via email or the message centre
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Types of Rocks
There are three types, Igneous, Metamorphic and Sedimentary.
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the surface and within bodies of water. 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 accumulating are called sediment. Examples of this rock are sandstone and limestone.
Igneous rock is formed through the cooling and solidification of magma or lava. An example of igneous rock is granite, whcih forms from the slow crystallisation of magma below Earth's surface
Metamorphic rocks arise 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. An example of this is marble.
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A few common rocks and identifying features
Marble is formed from limestone that has been subjected to intense pressure underground due to tectonic movement or through being subject to extreme heat. Marble itself is mainly composed of carbonate minerals, most commonly calcite or dolomite, it is generally light in colour, especially when formed from limestone that contains very few impurities. Marble that contains impurities such as clay minerals or iron oxides can be bluish, grey, pink, yellow or black in colour. It is a very tough rock and would feel very smooth even after years of exposure to the elements.
Slate is a fine-grained, foliated (banded), metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash. It is the finest grained foliated metamorphic rock. Slate occurs in a variety of colours from pale to dark, is waterproof and extremely durable, . Due to its durability it has often been used for tombstones and memorial tablets.
Granite This is an igneous rock made up of noticeably different crystals of different coloured minerals. Granite may contain crystal structures of different sizes. In some examples of granite, you may find phenocrysts. A phenocryst is an early forming, relatively large crystal distinctly larger than those of the rock groundmass (the surrounding material).
Sandstone is a sedimentary rock, it can be grey, red or yellow in colour. You will be able to identify the bedding planes which are lines that 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. 
Limestone is a sedimentary rock that mainly consists of the mineral calcium carbonate. The limestone is formed under the sea many millions of years ago, most often formed by depositing lime from different fossils with shells. This means that the limestone content reflects the environment that existed when deposited. A common building material especially in ancient times due to the decorative look of the rock and its propensity to being easily carved. This is often a light coloured rock, but other limestones may be variously coloured including darker colours. which suffers from chemical weathering, as a result of acid rain. It may contain bedding planes and many variety of fossils including corals, shells and marine life.
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Weathering:
Physical weathering is caused by physical processes such as changes in temperature, freezing and thawing, and the effects of wind, rain and waves. There are two main types of physical weathering:
Freeze-thaw occurs when water continually seeps into cracks and freezes which can break rocks, as if water gets into a crack into the rock, it freezes into ice, expanding the crack and making it bigger. This process then repeats itself with the crack in the rock getting bigger every time, eventually breaking the rock apart.
Exfoliation occurs as cracks develop parallel to the land surface a consequence of the reduction in pressure during uplift and erosion.
Chemical weathering occurs when rocks are affected by acids and corroded by solution weathering; rainfall is weak carbonic acid although this acidity can be increased by pollution. In the process of carbonation, rainwater and carbon dioxide in the atmosphere combine to form carbonic acid. This carbonic acid dissolves minerals within the rock, weakening the structure and resulting in damage and wear. Rocks made from carbonate minerals, chalk and marble for example, are particularly susceptible to chemical weathering. On statues or monuments this can also result in the appearance of staining on the surface.
Biological weathering is the impact of living organisms on the stone. Plants put down roots through joints or cracks in the rock in order to find moisture. As the plant grows, the roots gradually pull the rock apart. Many animals bore into rocks for protection either by scraping away the grains or secreting acid to dissolve the rock. Even the tiniest bacteria, algae and lichens produce chemicals that help break down the rock on which they live, so they can get the nutrients they need
Questions
1a. Observe the East side of the memorial (the road-side) by the text under the bronze panel. Please describe for me the colour, texture and general composition of the rock at this specific part of the cenotaph.
1b. From the EarthCache description and your answer to Q1a, what rock do you think the plinth is made from, and why?
2. Estimate the size of the grains you can see in the stone at this specific part of the memorial. Compare this with the rest of the memorial; how does the density of the grains differ and are they all a similar size?
3. Examine the main memorial block again, but this time looking for signs of weathering. Has it been affected by physical/chemical/biological weathering or a combination? Explain why you think this.
4. Please add a photo of you or your GPS at the memorial though not giving any answers away :)