A Church Micro earthcache on the subject of weathering and chemical deposits, placed at the church of St Matthew and St Wardrede in the village of Lee. This Earthcache has been placed with the kind permission of the vicar.
PLEASE NOTE: As this is an Earthcache, there is no container at the headline coordinates - you will need to email the answers to the questions below to my profile or send via Message Centre in order to claim a find.
LOGGING TASKS:
1) From the church porch you will see a large slate cliff behind the church. Looking at the three types of mechanical weathering shown below, please state a type of weathering that you can see in progress which is making the slates break apart and fall off.
2) Give evidence to show where you can see the weathering taking place.
3) Moving around to the front of the church now, you can see that some of the rocks making up the church are coloured slightly differently, however they are the same type mostly. This is due to mineral deposits within - suggest a mineral that could be in the rocks and give reasons for why you have chosen that mineral.
To prove you visited: In the church porch there is a plaque. Who were the external lights placed in memory of?
Please ensure you email or use the Message Centre to send me the answers within 24 hours of logging a find or you risk your log being deleted. You don't need to wait for permission to log.
GEOLOGY
WEATHERING
Freeze-thaw weathering: Water seeps into cracks in rocks and then when the temperature drops below freezing at night time, the water expands. The force that this exerts on the rock will widen the crack and break the rock apart.
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. Rocks like slate and granite are more resistant to acid rain due to the chemicals they contain.
Biological weathering: This happens when living organisms enter cracks in the rock and grow there. For instance, plant or tree roots can grow within the cracks and like freeze-thaw weathering, as the roots grow in size they will exert a force on the rock which will break it apart.
MINERAL DEPOSITS
Minerals are the building blocks of rock. Some rocks consist of just one type of mineral, but most rocks contain a few different types of minerals joined together. Each mineral has its own unique chemical composition, which helps to determine what color it will be. A mineral's color can also be affected by chemical impurities, interaction with other minerals, and environmental factors. Like all objects, a mineral's color depends upon which wavelengths of light it absorbs and reflects. The atomic bonds within a mineral generally determine which wavelengths of light will be absorbed and which will be reflected. Those wavelengths that are reflected back to our eyes determine the color of the mineral.
Chemical weathering, explained above, may also cause the color of rocks to change. For example, rocks containing iron tend to rust when they come into contact with oxygen or water. When they begin to rust, they turn reddish-brown. The amount of iron present determines the intensity of the color of the rock.
CHURCH INFORMATION
The Parish Church of St. Matthew or, more fully, of St. Matthew and St. Wardrede, was built in 1833-34 during the reign of William IV. It was consecrated by the Bishop as a chapel-of-ease in the Parish of llfracombe on St. Matthew's day 1835, and became a Parish Church in 1869, when Lee became a separate ecclesiastical parish carved out of the parishes of llfracombe and Mortehoe. The association with St. Wardrede is of uncertain origin, but the name is of interest in that it may point to an earlier Celtic missionary influence in Lee in the 6th century. "it is not known with certainty who St. Wardrede was" writes Mr. R. Barnes, formerly of the University of Leicester, who has investigated the matter. He "believes that he was a Celtic Saint, whose name is embodied in the Cornish name " Tywardreath " and that the Champernowne family, who were the lords of Tywardreath, as well as patrons of Ilfracombe, were probably responsible for the dedication." Like many other Celtic Saints he may have been known or remembered anonymously and simply as "Saint"= the holy man, "war"= on or near, "drede"=the beach.
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WHILE PICTURES OF THE CHURCH ARE WELCOME, PLEASE DO NOT UPLOAD ANY THAT COULD GIVE THE ANSWERS AWAY.
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