Triassic sand dunes
Thick beds of red sandstone. Probably deposited by wind as sand dunes.
This was once a quarry. The holes in the soft rock face have been left by quarrying operations.
Here 240 million years ago?
The sand dunes move forward in the direction of the wind.
By making measurements on the angles of dune bedding geologists can work out the main wind direction in the past. Today we get winds mainly from the west. In the Triassic it seems the main direction was from east or north-east.
This cross section of a sand dune, shows dune-bedding. Remember the lines you saw in the sandstones of the church walls.
Task Site 2a Questions
What is the colour of the rocks in the rock face?
What type of rock is this?
a) hard limestone
b) soft sandstone
c) hard sandstone
d) soft mudstone
In which environment might these types of rocks be forming today?
c) The Arctic
d) Coral reefs
Tap ‘then’ (in the app) to find the typical temperature here when these rocks were forming.
a) 5 degrees centigrade
b) 20 degrees centigrade
c) 100 degrees centigrade
d) 30 degrees centigrade
In which period of time were the rocks in front of you formed?