In the same way, by identifying fossils, he may have related Sedimentary Rocks B with some other rocks.
Creationists would generally agree with the above methods and use them in their geological work.
For example, a geologist may examine a cutting where the rocks appear as shown in Figure 1.
Here he can see that some curved sedimentary rocks have been cut vertically by a sheet of volcanic rock called a dyke.
The geologist may have found some fossils in Sedimentary Rocks A and discovered that they are similar to fossils found in some other rocks in the region.
Thus, he already ‘knows’ that the igneous dyke must be younger than 200 million years and older than 30 million years.
The field relationships are generally broad, and a wide range of ‘dates’ can be interpreted as the time when the lava solidified.
What would our geologist have thought if the date from the lab had been greater than 200 million years, say 350.5 ± 4.3 million years?
No matter what the radiometric date turned out to be, our geologist would always be able to ‘interpret’ it.
He would simply change his assumptions about the history of the rock to explain the result in a plausible way. Wasserburg, who received the 1986 Crafoord Prize in Geosciences, said, ‘There are no bad chronometers, only bad interpretations of them!