Radiometric dating methods geology
Radiometric dating methods geology - muckydating com
For example, it has been known since the 1960s that the famous Cretaceous-Tertiary boundary, the line marking the end of the dinosaurs, was 65 million years old.Repeated recalibrations and retests, using ever more sophisticated techniques and equipment, cannot shift that date. With modern, extremely precise, methods, error bars are often only 1% or so.
New discoveries have filled in the gaps, and shown us in unimaginable detail the shape of the great ‘tree of life’.
Today, innovative techniques provide further confirmation and understanding of the history of life.
Biologists actually have at their disposal several independent ways of looking at the history of life - not only from the order of fossils in the rocks, but also through phylogenetic trees. Relative dating is done by observing fossils, as described above, and recording which fossil is younger, which is older.
The discovery of means for absolute dating in the early 1900s was a huge advance.
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.
The fossil record is fundamental to an understanding of evolution.
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.Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.The universe is full of naturally occurring radioactive elements.Radioactive atoms are inherently unstable; over time, radioactive "parent atoms" decay into stable "daughter atoms." When molten rock cools, forming what are called igneous rocks, radioactive atoms are trapped inside. By measuring the quantity of unstable atoms left in a rock and comparing it to the quantity of stable daughter atoms in the rock, scientists can estimate the amount of time that has passed since that rock formed.Geologists and paleontologists are highly self-critical, and they have worried for decades about these issues. D., is a vertebrate paleontologist with particular interests in dinosaur origins and fossil history.