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Mineral 87 Sr/ 86 Sr 87 Rb/ 86 Sr ______________________________________________

ID: 914625 • Letter: M

Question

                     Mineral                     87Sr/86Sr                         87Rb/86Sr

    __________________________________________________________

                     1                          0.706196                            0.20

                     2                          0.709965                            0.83

                     3                          0.713973                            1.50

                     4                          0.723544                            3.10

          __________________________________________________________

Explanation / Answer

In isochrom method we plot 87Sr/86Sr (y) against 87Rb/86Sr (x)

we will compare the graph with

y = c + x m

The slope of line will give age of mineral and the intercept (c) gives the initial 87Sr/86Sr ratio of the system

So the slope = age of mineral = 0.0082

And intercept = 0.5464