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Relative rock layers

Note: Click the picture below to open Relative rock layers in a popup. You will need the Adobe Flash Player to view it.

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This interactive asks you to use your knowledge of relative dating. You need to work out the order in which rocks were formed, from youngest to oldest.



We’ve found this cliff. Help us work out the relative ages of the layers of sedimentary rocks.
Remember that younger sedimentary rocks lie on top of older ones and were horizontal when formed.
It looks as though one group of layers was tilted and eroded away before new rocks were formed on top.


Move your mouse over one of the geologist’s hammers. Information about one of the rock layers will appear – drag the hammer and drop it onto the layer you think is being described.
Carry on and place all the hammers on the correct layers.

The oldest rock is below all the others.
This rock is just above the oldest.
This is the thinnest rock layer.
This was the last layer to be formed before the rocks tilted.
This layer formed on top of earlier rocks after they were tilted and eroded away.
This is the youngest rock above all the others.