Start Facts about geologic dating

Facts about geologic dating

Let us imagine that the date reported by the lab was 150.7 ± 2.8 million years.

Here he can see that some curved sedimentary rocks have been cut vertically by a sheet of volcanic rock called a dyke.

In other words, the age should lie between 197.2 million years and 203.6 million years.

However, this error is not the real error on the date.

From his research, our evolutionary geologist may have discovered that other geologists believe that Sedimentary Rocks A are 200 million years old and Sedimentary Rocks B are 30 million years old.

Thus, he already ‘knows’ that the igneous dyke must be younger than 200 million years and older than 30 million years.

Would he have concluded that the fossil date for the sediments was wrong? Would he have thought that the radiometric dating method was flawed? Instead of questioning the method, he would say that the radiometric date was not recording the time that the rock solidified.

He may suggest that the rock contained crystals (called xenocrysts) that formed long before the rock solidified and that these crystals gave an older date.

He may suggest that some other very old material had contaminated the lava as it passed through the earth.