Radiometric dating of surface rocks
I'm a biology teacher and would like to be able to explain this method clearly to my students. In the example of K-Ar: Diffusion of Ar is so fast that a given mineral should have completely degassed all of it's Ar once the mineral cooled below a certain temperature.I'm good with carbon dating of biological materials but the inorganic dating has always been a puzzle for me. In this case, the initial concentration of Ar is zero.I'm not sure how big of an issue this is with monazite or xenotime.But I just submitted a paper that uses this technique for titanite.Radiometric dating is the principal source of information about the absolute age of rocks and other geological features, including the age of the Earth itself, and can be used to date a wide range of natural and man-made materials.You can't date all minerals using the radiometric dating method because not all minerals have radioactive isotopes.The data obtained on lunar samples brought to light the importance during planet growth of highly energetic collisions that lead to global-scale melting.This violent birth determines the initial structure and long-term evolution of planets.
The y-intercept of the isochron is therefore the initial daughter. We measure the mass of Pb-204, which is the only Pb isotope that is not the product of radioactive decay.There are different methods of radiometric dating, and they apply to different things and they have different lengths of time, at least as… What I'm having difficulty with is how we know the initial proportions.I can't remember how other systems treat this problem off the top of my head (for example Sm-Nd, Re-Os, Rb-Sr), or how this problem is addressed with whole rock isochron dating. The radiogenic daughters can be present at formation and we can still get an age.We use isochrons to estimate the initial for systems like Sm-Nd, Rb-Sr, and (most) Re-Os.