TABLE 1 Results of Isotopic Analyses Rock UnitNumber of Parent AtomsNumber of Daughter Atoms A 74971071 B114803827 C 8392517 Radioactive parent isotopes decay at a constant ra

1. To find the absolute age of unit A, we need to use the formula:

t = -(1/λ) * ln(Pt/Po)

where t is the age in years, λ is the decay constant (which is equal to ln(2)/half-life), Pt is the number of parent atoms today (7497), and Po is the number of parent atoms originally present (Pt + number of daughter atoms today).

Po = Pt + Dt Po = 7497 + 1071 Po = 8568

Now we can calculate the age:

t = -(1/λ) * ln(Pt/Po) t = -(1/0.000121) * ln(1071/8568) t = 22,200 years

Therefore, the absolute age of unit A is 22,200 years.

2. To find the absolute age of unit B, we use the same formula:

Po = Pt + Dt Po = 11,480 + 3,827 Po = 15,307

t = -(1/λ) * ln(Pt/Po) t = -(1/0.000121) * ln(3827/15307) t = 45,500 years

Therefore, the absolute age of unit B is 45,500 years.

3. To find the absolute age of unit C, we use the same formula:

Po = Pt + Dt Po = 8,397 + 25,117 Po = 33,514

t = -(1/λ) * ln(Pt/Po) t = -(1/0.000121) * ln(2517/33514) t = 216,800 years

Therefore, the absolute age of unit C is 216,800 years.

4. According to the chart, the correct order of the observed layers from oldest to youngest should be C, B, A. Our measured ages support this order, as the age of C is much older than the ages of B and A. This is consistent with the principles of relative dating, which state that older rocks are found beneath younger rocks in undisturbed sequences. The folding and deformation observed in unit C may have occurred after the deposition of units B and A, which is why they are not folded or deformed