However, if the clocks change and you forget to reset your wrist watch, then you have a very precise time but it is not very accurate – you will be an hour early or late for all of your meetings!See the difference between accurate and precise measurements in the bull’s eye figure below.), then many of your boulders may have rolled or been covered with snow. It is the job of the scientist to sample carefully to minimise these potential sources of inaccuracies in cosmogenic nuclide dating.
Scientists want measurements that are both accurate and precise…
but it can be difficult to tell sometimes whether very precise measurements are actually accurate without an independent reference age (see top right image versus bottom right image).
It is therefore very important to sample landforms where partial bleaching is likely to be minimal. Measurements on ages are often reported very precisely, and ever-improving laboratory techniques mean that uncertainties are always decreasing.
But it is important not to take these ages at face value, and to think critically about whether or not they may be accurate.
Be) atoms in a boulder yield measurements of an exposure age with very low uncertainties. This analytical uncertainty does not take into account geological uncertainties – has your boulder rolled over, or has it been reworked and does it contain Be from a previous exposure?