Isochron Diagrams

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 clicking on the "up" or "down" arrows. This line, called an Isochron, increases in slope as time passes.

Answer the question, then click Next
1. At what point in time do all of the mineral separates have the same amount of daughter isotope (D)?
  0.0 half-lives
  0.5 half-lives
  exactly 1.0 half-lives
  It's impossible to know

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