How does radioactive dating occur
Also includes info on how fossils are formed, the “cleaning, preparing, & repairing” of fossils, and other useful resources.
In 1896, the French physicist Antoine Henri Becquerel accidentally found that a uranium-rich mineral called pitchblende emitted invisible, penetrating rays that could darken a photographic plate enclosed in an opaque envelope.
All these labors have not led to a single unexpected finding such as a human fossil from the time of the dinosaurs, or a Jurassic dinosaur in the same rocks as Silurian trilobites.
Paleontologists now apply sophisticated mathematical techniques to assess the relative quality of particular fossil successions, as well as the entire fossil record.
Age estimates can be cross-tested by using different isotope pairs.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.Fossils can also show us how major crises, such as mass extinctions, happened, and how life recovered after them.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.