The acids are changed daily

Cosmogenic nuclide dating methods anthropology

This can result in a complex exposure history. Topographic shielding and shielding by snow, vegetation or soil is also taken into account. Scientists must therefore carefully measure the horizon line all for degrees all around their boulder. This varies with altitude and latitude.

The acids are changed daily. Trimlines can therefore also be used to reconstruct past ice sheet thickness.

Attenuation of cosmic rays Bethan Davies sampling a boulder for cosmogenic nuclide dating in Greenland. This is called inheritance. For a rock to be suitable for cosmogenic nuclide dating, quartz must occur in the rock in sufficient quantities and in the sufficient size fraction. More slowly decaying isotopes are useful for longer periods of time, but less accurate in absolute years. The more durable quartz is left behind.

Attenuation of cosmic rays Bethan Davies

Cartoon illustrating cosmogenic nuclide exposure ages. Such path is constructed for a large continental block.

Further reading The video below, produced by Science Bulletins, National Centre for Science Library, nicely and simply illustrates the core concepts in cosmogenic exposure age dating. Wherever we are on Earth, when we are outside, we are constantly bombarded by these cosmic rays.

This is called inheritance