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How a grain of sand reveals an entire history
The landscape changes over time, for example due to climate change or rising sea levels. But when exactly were these dykes, river deposits or dunes formed? Researchers are looking at grains of sand for the answer.
Because a grain of sand holds all kinds of information. Like when the grain last encountered light. And this information can tell us more about its age.
How we get the information out of the grains
To extract this information from the sand, we take the grains to the Netherlands Center for Luminescence dating (NCL) in Wageningen. It is important that the samples are taken and transported in such a way that no light gets in.
In the dark laboratory, we stimulate the grains and then photograph the luminescence signal released by these grains with a very sensitive camera. This camera can visualise the 'light signal'. By measuring how much light is released, we can find out how long each grain of sand has been in a dike, for example. By determining the average of a number of grains, we can find out how old the dike is.
We are also trying to find out the origin of a grain of sand, which we can use to map the distribution of sand that has been deposited. Valuable information for further research!
Jakob Wallinga takes you inside the laboratory:
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An example of several grains emitting light, captured in one image. The red circle in the left-middle shows a bright sand grain emitting luminescence; the other circles are for positioning.