Difference between radiometric absolute dating

The simplest form of isotopic age computation involves substituting three measurements into an equation of four variables, and solving for the fourth.

difference between radiometric absolute dating-16

It is not easily explained, in the general case, in any other way.

The data points would be expected to start out on a line if certain initial conditions were met.

Consider some molten rock in which isotopes and elements are distributed in a reasonably homogeneous manner.

Its composition would be represented as a single point on the isochron plot: Note that the above is somewhat simplified.

The wonderful property of isochron methods is: if one of these requirements is violated, it is nearly certain that the data will indicate the problem by failure to plot on a line.

(This topic will be discussed in much more detail below.) Where the simple methods will produce an incorrect age, isochron methods will generally indicate the unsuitability of the object for dating.

This will be discussed in more detail in the section on Gill's paper below.

The "generic" method described by Gonick is easier to understand, but it does not handle such necessities as: (1) varying levels of uncertainty in the X- versus Y-measurements of the data; (2) computing an uncertainty in slope and Y-intercept from the data; and (3) testing whether the "fit" of the data to the line is good enough to imply that the isochron yields a valid age.

It depends on the accuracy of the measurements and the fit of the data to the line in each individual case.) For example, with Rb/Sr isochron dating, any age less than a few tens of millions of years is usually indistinguishable from zero.

Tags: , ,