How do scientists use fossils and ages of rock samples to help fill in information on the geological time scale?

1 Answer
Apr 2, 2018

Fossils are the bases of the geological time scale Using the principle of descent with modification proposed by Charles Darwin rock samples are dated using fossils.


The simpler fossils are assumed to be older than complex fossils. The geological time scale was developed based on the complexity of the fossils found in the rocks.

No paleontologist worthy of the name would ever date his fossils by the strata in which they are found....fossils have been and still are the best and most accurate method of dating and correlating the rocks in which they occur. Ager New Scientist 1983 425.

The Sedimentary rocks by themselves do not yield any specific time marks, setting aside the old law of superposition which can provide relative age indictions only in a restricted manner and which is unfit for age correlations. Moreover it may be misleading in some cause the beds in a section may be over turned or owing to a hidden thrust plane older beds may overlie younger ones. American Journal of Science June 57 p 394.

The fossils are used to establish the geological time scale, Fossils determined to be older are often found on top of fossils thought to be younger. The geological time scale is base on Darwinian evolutionary theory.