Welcome to Kippen Parish Church. A red sandstone church building in the village of Kippen, Stirlingshire.
We are here today for an EarthCache looking at two physical characteristics of the sandstone. We are looking at bedding planes and we are looking at mineral-filled cracks in the sandstone. The first is an indication of the environment where the sandstone was formed. The second is an indication of what may have happened to the sandstone after it was formed.
Horizontal bedding:
Horizontal bedding is where the layers of sediment that came to form the sandstone were deposited in a general calm environment of slow moving grains of material. This would generally have occured on the beds of large bodies of water where the speed of the water movement has slowed sufficiently for the material to settle out of suspension. It also needs the water to not have been moving quickly enough to have resuspended the material or to have disturbed the surface of the deposition into ripples.
Cross bedding:
Cross bedding occurs when the layers of deposited material have been laid down in a faster moving environment. They then take the shape of the bed of that environment. This could be either from the bends of a riverbed, meaning that the grains are laid down with flow of the water leading to a banking effect in the sediment, or in dunes where the movement of the wind leads to the grains being laid down and shaped by the forces of the wind moving over the surface. This leads to the banked shape of sand dunes around our coasts.
Where sandstone with different bedding is found in close proximity, then the differences can be seen clearly. This could be on an exposed rock face, or as here, in different blocks of stone.
Mineral-filled cracks.
Sandstone as a material is strong in compression, when it is be squashed. It is not could in tension, when it is being pulled. If the sandstone is pulled, it will eventually crack/split. These cracks are known in geological terms as "faults". The faults can be massive and caused by large movements of the rock, or micro faults caused by movements over a small distance and only affecting a small area of the rock.
These cracks are subsequently filled with something. This can be small pieces of rock, liquids such as water which can dissolve the minerals in the surrounding rock, or other rocks under pressure (such as magma). Here we shall look at two examples of these cracks being filled with minerals.
So that's what we're hoping to learn here. Now, on to the questions.
Sandstone bedding
1) Look at the buttress at the corner to the right of the door in front of you. Look at the second and third courses/layers of sandstone on the end of the buttress. Considering what you have learned above, which shows horizontally bedded sandstone and which shows cross bedded sandstone?
Mineral filled cracks
We will now look at two locations on the building.
The first is a roughened stone, to the right of the door, about 6' (1.8m) above the ground.
2) Roughly how wide is the mineral filled crack?
3) Can you describe the mineral in terms of colour and whether there are obvious individual crystals?
Now look at the buttress to the left of the Kippen Parish Church sign, and an area about 5' (1.5m) above the ground on the end of the buttress.
4) Can you now describe the size and grouping of the mineral filled cracks here?
5) Finally, to show that you have visited the location, please take a photo of yourself or a personal item showing the pebble mosaic on the ground as well.
Please send me the answers to the questions by email or message through my profile. Do not include these in your log. Please upload your photo to your log.