Radioactive dating sedimentary rock
Radioactive dating sedimentary rock - greek dating in australia
Rubidium-strontium dating is more robust, and uranium-lead dating can survive fairly significant metamorphism without resetting.If a system gains or loses isotopes in a predictable way, it may be possible to estimate the loss and correct the age.
If there were such a pair of isotopes, radiometric dating would be very simple.
Sedimentary rocks are generally hard to date because common cements like silica don't have datable radioisotopes, and minerals like glauconite that are common in sedimentary rocks are very prone to resetting.
If only there were long-lived isotopes of silicon, calcium, and magnesium!
But there are some questions that come to mind: Calculus students typically meet this problem somewhere in the second semester.
It is one of the simplest examples of a differential equation.
Crystallization of a mineral is a good way to close a system. Any disturbance of the system effectively resets the clock to zero by allowing decay products to escape or reshuffling the abundances of elements.
Weathering and metamorphism are the two most common ways to disturb a system.
In other words there was originally 4 parts per million Parentium-123 and 0 parts per million Daughterium-123.
Since there is now only 1/4 of the original amount of Parentium-123, we know that two half-lives of Parentium-123 have elapsed.
So: The general approach to assessing gain or loss is to look at the isotope abundances in different minerals and see if there's a pattern.
If the ratio is constant, we can be pretty sure there's been no gain or loss.
When t = 0, ln N(0) = C Taking exponentials of both sides, we get N(t) = N(0)exp(-Kt) If t = one half life, then N(t)/N(0) = 1/2 = exp(-Kt), and: ln(1/2) = -ln2 = -Kt, so t = ln2 / K So what we do in practice is determine the decay constant and calculate half life from it.