In fact, he would have been equally happy with any date a bit less than 200 million years or a bit more than 30 million years.
They would all have fitted nicely into the field relationships that he had observed and his interpretation of them.
Clearly, Sedimentary Rocks A were deposited and deformed before the Volcanic Dyke intruded them.
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!
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.
He may suggest that some other very old material had contaminated the lava as it passed through the earth.