Cosmogenic exposure dating

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Since the cosmic ray spallation route is the only possible source of beryllium-7 and beryllium-10 occurrence naturally in the environment, they are therefore isotopes produced within solid earth materials, such as rock, samples are generally first put through a process of mechanical separation.

Be production rate is carefully calibrated, for example by correcting for partial attenuation and complete shielding effects.

This is because the earth’s magnetic field varies in strength and polarity direction.

This is caused by a number of factors, including variations in solar radiation, magnetic storms, and internal geophysical factors.

This information is vital for numerical models, and answers questions about how dynamic ice sheets are, and how responsive they are to changes in atmospheric and oceanic temperatures.

Many methods are only useful for a limited period of time (for radiocarbon, for example, 40,000 years is the maximum age possible).

Scientists dating Quaternary glacial sediments in Antarctica most commonly use one of the methods outlined below, depending on what kind of material they want to date and how old it is.

Radiocarbon dating dates the decay of Carbon-14 within organic matter.

Organic matter needs to have been buried and preserved for this technique. It assumes that organic material is not contaminated with older radiocarbon (which, for example, is a common problem with organic material from marine sediment cores around Antarctica).

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