Relative rock layers
Use this interactive to work out the relative ages of some rock layers from youngest to oldest. Drag and drop the text labels onto the diagram. Selecting or hovering over a box will highlight each area in the diagram. If you hover your mouse over the text labels there is more information about the rock layers.
If you want to redo an answer, click on the box and the answer will go back to the top so you can move it to another box. If you want to check your answers, use the Reset incorrect button. This will reset incorrect answers only. When you are happy with your selection, use the Check answers button to check them. Use Reset all to practise again from the start.
If you haven't already, we recommend you watch this animation before you use the interactive.
Scientists use relative dating to arrange geological events, and the rocks they leave behind, in a sequence. The method of reading the order is called stratigraphy (layers of rock are called strata).
Check out this cliff. It looks as though one group of layers was tilted and eroded away before new rocks were formed on top. Help us work out the relative ages of the layers of sedimentary rocks, from youngest to oldest. Remember that the younger sedimentary rocks lie on top of older ones and were horizontal when formed.
This interactive is part of the Rock layers and relative dating activity.
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Use the Download Exercise button for a PDF version of this interactive.
| Label | Description |
|---|---|
youngest rock pre-tilt | This was the last layer to be formed before the rocks tilted. |
oldest rock pre-tilt | This rock layer is below all the others. |
youngest rock post-tilt | This is the youngest rock above all the others. |
second-oldest rock | This rock layer is just above the oldest. |
thinnest rock | This is the thinnest rock layer. |
oldest rock post-tilt | This layer formed on top of earlier rocks after they were tilted and eroded away. |
