What is fossil dating

Posted by / 27-Mar-2015 00:44

What is fossil dating

Radiocarbon dates come from organic matter that contain the element carbon.

Ice cores, pollen, wood, hair, bone, shell, bird egg shell, and coral are some of the things datable by this technology which depends on measuring the atomic decay rate of carbon isotopes.

The oldest uncontested fossils on earth are 2 billion year-old stromatolites in Minnesota, Wisconsin, and Ontario.

Composed of layers of sediments laid down by colonies of cyanobacteria, stromatolites still exist, but are quite rare today.

Organisms usually need to be covered by mud, sand, tar or some other sediment as soon as possible or frozen or dessicated (dried out) for fossilization to occur.

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

Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.

The rejection of the validity of fossils and of dating by religious fundamentalists creates a problem for them: Fossil sequences were recognized and established in their broad outlines long before Charles Darwin had even thought of evolution.

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.

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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.