Ways dating fossils

15-May-2019 04:21

Early geologists, in the 1700s and 1800s, noticed how fossils seemed to occur in sequences: certain assemblages of fossils were always found below other assemblages. Since 1859, paleontologists, or fossil experts, have searched the world for fossils.

In the past 150 years they have not found any fossils that Darwin would not have expected.

A key point is that it is no longer necessary simply to accept one chemical determination of a rock’s age.

Age estimates can be cross-tested by using different isotope pairs.

Estimating the dates of these remains is essential but difficult: sometimes adjacent rock layers allow radiometric dating, which provides absolute dates that are accurate to within 0.5%, but more often paleontologists have to rely on relative dating by solving the "jigsaw puzzles" of biostratigraphy.

Paleontologists now apply sophisticated mathematical techniques to assess the relative quality of particular fossil successions, as well as the entire fossil record.

The methods are all based on radioactive decay: The first radiometric dates, generated about 1920, showed that the Earth was hundreds of millions, or billions, of years old.

Since then, geologists have made many tens of thousands of radiometric age determinations, and they have refined the earlier estimates.

Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.

These skeptics do not provide scientific evidence for their views.

Paleontologists now apply sophisticated mathematical techniques to assess the relative quality of particular fossil successions, as well as the entire fossil record.

The methods are all based on radioactive decay: The first radiometric dates, generated about 1920, showed that the Earth was hundreds of millions, or billions, of years old.

Since then, geologists have made many tens of thousands of radiometric age determinations, and they have refined the earlier estimates.

Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.

These skeptics do not provide scientific evidence for their views.

Fossils document the order of appearance of groups and they tell us about some of the amazing plants and animals that died out long ago.