This part of the age-dating activity involves plotting points and adjusting the slope of lines within an x-y coordinate system. If you need some practice, click HERE.

The points (M1, M2, and M3) represent the ratios of parent/daughter isotopic compositions of three minerals.

Adjust the slope of the line connecting the points by moving the slider to the right and left. This line, called an Isochron, increases in slope as time passes.