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An EarthCache provides an earth science lesson through a visit to a geological feature. This EarthCache concerns the weathering of Limestone. There is no physical container to find, just information.
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Scott Memorial, Mount Wise, Devonport, Plymouth.
Robert Falcon Scott was born in Devonport on 6 June 1868 at his family's home, Outlands. He became a naval officer, and subsequently led the British Antarctic Expedition of 1910–13 in search of the South Pole. The members of his team were Lawrence Oates, Henry Bowers, Edgar Evans and Edward Wilson. The team reached the pole in January 1912 only to learn that Norwegian Roald Amundsen and his team had beaten them to it, arriving there one month earlier in December 1911. On the journey home Scott and all his men perished.
Devonport honours the memory of the British team with the beautiful Scott Memorial at Mount Wise Park. The memorial was unveiled on 10 August 1925 by the Commodore of the Royal Naval Barracks, C W R Royds, who had accompanied Scott on a previous expedition. It is now a Grade II listed structure, listed by English Heritage on 1 May 1975.
2018 marks the 150th Anniversary of Scott's birth - there will be local & national events marking this, so it seems appropriate to add an EarthCache to this wonderful memorial to a national hero.
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Please read the information below as it will help you to answer the EarthCache questions.
What is Limestone?
Limestone is a sedimentary rock. This sediment is formed by very many tiny particles which laid down deposits over millions of years. These were composed mainly of skeletal fragments of marine organisms such as coral and molluscs. As the sediment layers build up they are pressed together to form sedimentary rock.
Limestone has numerous uses: as a building material, an essential component of concrete (Portland cement), as aggregate for the base of roads, as white pigment or filler in products such as toothpaste or paints, as a chemical feedstock for the production of lime, as a soil conditioner, or as a popular decorative addition to rock gardens.
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Weathering
This describes the breakdown of rock through exposure to the atmosphere. It can happen in three main ways...
1. Chemical Weathering
Rainwater is naturally slightly acidic because carbon dioxide from the air dissolves in it. Minerals in rocks may react with the rainwater, causing the rock to be weathered.
Some types of rock are easily weathered by chemicals. For example, limestone and chalk are made of a mineral called calcium carbonate. When acidic rainwater falls on limestone or chalk, a chemical reaction happens. New soluble substances are formed in the reaction. These are washed away and the rock is weathered.
Chemical weathering can hollow out caves form and make cliffs fall away.
2. Biological Weathering
This can cause the breaking and/or crumbling of the stones by tree roots, plants or animals. Also common is the damage caused by lichens or organisms growing on the surface of rocks. Lichen takes the nutrients it needs from the surface of the limestone. Changes in the composition of the rocks can weaken them.
3. Physical Weathering
Weathering from physical factors can change the shape of the rock, rather than the actual composition. Heat can expand stones, while cold will cause contraction. This process over a period of time will cause the stones to fracture and crack. Rainwater can then also seep into cracks in the rock, and, if frozen, will expand and make these cracks bigger and wider.
Wind can also affect loose grains of stone, causing more damage
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Hopefully the information above has given you some new and interesting facts to play with. Use your new found knowledge to answer the following questions to help you to log this EarthCache. The questions relate to how the stone has been affected by weathering over the last (nearly) hundred years.
1. You will see as you face the statue of Scott, there is a carved inscription starting 'Had we lived...' Please describe the what effect weathering has had on the this carving (words on the right are a good example) and which type of weathering do you think is responsible for this effect?
2. Much of the stone on the seaside of the monument appears a different colour to the farside. Please tell me why and how this discolouration has occured here rather than across the whole structure.
3. Finally, from the 'front' of the memorial, under the list of team members, please tell me the date carved at the bottom of the inscription.
You can send your answers to me via the website message centre, or email, but feel free to log your visit.
Photos of cachers visits to the site are appreciated (please try to avoid giving away any spoilers in your shots!) but not a requirement for logging. I hope you enjoy this EarthCache, and the surrounding parks and views!
Additional Hints
(Decrypt)
Vg'f n junpxvat terng zbahzrag ba n uvyyfvqr!