Please Note :
The carpark is set back from road .
It has caused confusion as entrance is shared with private residence but will become obvious as you drive past there driveway.
There is also a animal tomb stone in the carpark next to fence.
Welcome to St Swithun's church in Brookthorpe. This church is mainly 13th-century limestone This Grade 11 listed church also has some listed graves stones. This Earthcache is about the weathering of limestone.
This Earthcache is about the weathering of limestone.
What is Limestone?
Limestone is a sedimentary rock. This means that small particles of stone created it, along with shells, molluscs and now-fossilised sea creatures and marine organisms millions of years ago.Sedimentary rocks are formed from layers of deposits laid down in lakes or seas. Over millions of years, the sediment layers build up and the weight of these layers causes pressure, squashing them together.
This can also happen on land as the wind blows sediments on top of each other just like the formation of sand dunes.
Limestone is used worldwide in manufacturing and is also an invaluable building resource.
Weathering
This describes the breaking down of the rocks on the surface of the earth through exposure to the atmosphere in three main ways.
Chemical
Limestone as it is mainly made up of calcium carbonate. This is because the composition of the shells and organisms sedimented into the rock are made up of calcium carbonate.
Calcium carbonate reacts with rainwater.E.g., Carbon dioxide dissolves in rainwater. This causes carbonation that dissolves, leaving the stone with a rough, bubbly texture.
Oxygen dissolved in water will cause oxidisation, thereby changing the colour of the rock.
Biological
Biological weathering is caused by the breaking and crumbling of the stone by tree roots, plants or animals. More common in this churchyard is the damage done by organisms and lichen growing on the surface of the rocks. The lichen takes all of the nutrients that it needs from the stones. Changes in the composition of the rocks are making them weak. (Please do not touch the lichen on the stones as some are very rare and play a significant role in the local ecology).
Physical
Weathering caused by physical factors changes the shape of the rock, not its composition. The heat expands the stones and the cold contracts the stones. This process over a period of time may cause the stones to fracture and crack.
Rainwater can seep in through the cracks and when it freezes, the water turns to ice and expands slightly, making the cracks bigger.The wind can blow away stone grains and cause damage.
LOGGING QUESTIONS
Just inside the church porch, have a look at the stone benches on both sides of the wall. They have been affected much less by weathering as the porch is covering them.
Looking at the large chest-shaped tombs directly in front of the porch of which you can base your answers on either tomb.
These dates back to 1666.
1) How many types of weathering can you see on these tombs?
2) Looking at the gravestones, Describe what weathering has done to these tombs from what you can see?
You may use some examples from the information you have read.
3) This church is now redundant but is it still consecrated? (Answer easily found in porch)
Please log then send me the Answers via a message or email.
(Optional) If the door to the church is open, you are welcome to look around this beautiful church.
(Optional) sign the book inside the church, recording your visit.
This Earthcache has been placed with kind permission from the churches conservation trust.
#Well done graham&linda FTF
****************** ********************
For full information on how you can expand the Church Micro series by sadexploration please read the Place your own Church Micro page before you contact him at churchmicro.co.uk
See also the Church Micro Statistics and Home pages for further information about the series.
****************** *******************