So we knew about "deep time," but exploring it was frustrating.For more than a hundred years the best method of arranging its history was the use of fossils or biostratigraphy.
Clearly, Sedimentary Rocks A were deposited and deformed before the Volcanic Dyke intruded them.
These were then eroded and Sedimentary Rocks B were deposited.
Along the way, we'll learn how stratigraphic succession and radioactive decay contribute to the work of paleontologists.
Consider the following scenario: Paul the Paleontologist is a very famous scientist who has studied dinosaur bones all over the world.
by Tas Walker A geologist works out the relative age of a rock by carefully studying where the rock is found in the field.
The field relationships, as they are called, are of primary importance and all radiometric dates are evaluated against them.
The work of geologists is to tell the true story of Earth's history—more precisely, a story of Earth's history that is ever more true.
A hundred years ago, we had little idea of the story's length—we had no good yardstick for time.
A hundred years ago, our ideas about the ages of rocks and the age of the Earth were vague. Judging from the amount of rocks there are, plus the imperceptible rates of the processes forming them—erosion, burial, fossilization, uplift—the geologic record must represent untold millions of years of time.