How Old is the Earth: Radiometric Dating How Old is the Earth: Radiometric Dating

Radiometric dating basalt, a response to “scientific” creationism

Certain fossils also accumulate in a distinctive pattern or position that serves to define the top side. The difficulties associated are numerous and listed as follows: So the loss of a tiny amount of argon can have significant effects over long time periods.

So even if the crystal excludes the daughter element, it could be present in impurities. Relative ages are assigned to rocks based on the idea that rock layers lower in the strata were deposited before rock layers that are higher.

General considerations

So a rock can get a very old radiometric age just by having average amounts of potassium and argon. The time it takes for one half of the parent atoms to decay to the daughter atoms is called the half-life.

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Episodes of global volcanic activityrifting of continents, folding, and metamorphism are defined by absolute ages. Black lava, or basaltthe most common volcanic rock on Earth, provides a simple means for determining the depositional tops of rock sequences as well as proof of the antiquity of the oceans.

In this situation, fragments of the host rock must be found within the intrusive body to establish its relatively younger age.

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In his study Rutherford measured the U and He He is an intermediate decay product of U contents of uranium-bearing minerals to calculate an age. But the value is not really known.

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Tools for Digging Deeper. There are some very serious objections to using the potassium-argon decay family as a Radiometric dating basalt clock.

So if we take a lava flow and date several minerals for which one knows the daughter element is excluded, we should always get the exact same date, and it should agree with the accepted age of the geological period. On another point, if we can detect minerals that were not molten with the lava, as has been claimed, then this is one more reason why there should be no anomalies, and radiometric dating should be a completely solved problem.

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This would be less than one part in a trillion entering the rock each day, on the average. The precise measure of geologic time has proven to be the essential tool for Radiometric dating basalt the global tectonic processes that have taken place in the past.

It could be that this argon which is initially loosely bound if it is so initially gradually becomes more tightly bound by random thermal vibrations, until it becomes undetectable by the spectrum technique.

This suggests that what is occuring is some kind of a mixing phenomenon, and not an isochron reflecting a true age.

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Such samples are rare, and so nearly all modern Rb-Sr dating is done by the isochron method. Evidence for the period of accelerated decay is found in zircon crystals. If radiometric dating techniques are objective and accurate, then comparing the single—sample dates to the isochron dates should give similar results.

Let us consider again the claim that radiometric dates for a given geologic period agree with each other.