Cheddar Gorge And Gough's Cave Flashcards
Formation of cheddar gorge?
Represents an old river channel
At the end of different ice ages, a torrent of meltwater swept through the gorge and eroded downwards
Today, it is 400ft deep and 3 miles long
Formation of the mendips?
Formed in a shallow warm sea about 300 million years ago- Carboniferous period
The hills formed due to tectonic movements that formed an anticline
The area was not ice covered but it experienced torrential floods as ice sheets melted during interglacials.
Formation of the caves?
During the interglacials, meltwater from the ice sheets filled up the joints and bedding planes of the limestone
Carbonation helped to enlarge the joints and bedding planes
The flowing water also eroded the joints and bedding planes, and the combination of weathering and erosion enlarged joints and bedding planes to form caves
Angle of slope in the side of the gorge?
The top of the gorge starts off fairly gently sloped
In the gorge there are almost vertical sides
There are bedding planes
Cheddar gorge vegetation type and quality?
On cliffs
Very little vegetation and soil (mainly bare rock)
Soil is not very good quality and it’s very thin because the rock gets dissolved
On exposed areas
Grass
In more sheltered areas- shrubs, bushes, small trees
Cheddar gorge landuse?
ON THE PLATEAU Shooting Farming Grazing Farm buildings Walking
ON THE SIDE OF THE GORGE Sheep grazing Soil very thin Climbers- cliff faces Very steep No sediment Vegetation varies
BOTTOM OF GORGE Tourists- Few shops Car parks Road Cafes Caves open to public
If you look carefully, you can see some cave entrances half way up the gorge side. What does this reveal about how the gorge has changed over the past millions of years?
There has been more erosion in the gorge, lowering the floor and creating new entrances
How was the gorge formed?
Explain
At the end of the last ice age, the meltwater from the ice would have carved out the valley
When the sea level dropped, the river was encouraged to erode downwards
The entire gorge is a line of weakness
What is the difference between bedding planes and joints?
Bedding planes are lines of weakness that separate the layers of limestone that are generally horizontal
Joints are cracks in the rock that are generally vertical
How are the pot holes on the ceiling near the entrance formed?
Hydronic pressure
The caves are flooded and the water carves out the holes
Give some statistics to show how slowly the limestone features form
1cm 3 every 1200-1500 years
What is an inter-glacial?
A warm time between two glaciations (when we had the melting of the ice and water eroding the gorge)
Describe how climatic variations have altered gough’s cave
Inter-glacial meant more water so more erosion and more chambers formed
How are the different colours of the features formed?
PURE WHITE
Calcite deposits
RUSTY BROWN/RED
Iron
GREENY-BLUE
copper
GREY/SILVER
lead
Explain the formation of a stalactite
You can have a straw, curtain or candle stalactite
Water drips from the cave roof and it leaves behind calcite
