dating after divorce rebound relationship - Radiometric age dating

My purpose here is not to review and discuss all of the dating methods in use.Instead, I describe briefly only the three principal methods. These are the three methods most commonly used by scientists to determine the ages of rocks because they have the broadest range of applicability and are highly reliable when properly used.

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Radiometric dating is based on the decay of long-lived radioactive isotopes that occur naturally in rocks and minerals.

These parent isotopes decay to stable daughter isotopes at rates that can be measured experimentally and are effectively constant over time regardless of physical or chemical conditions.

Bishop James Ussher, a 17th-century Irish cleric, for example, calculated that creation occurred in 4004 B. There were many other such estimates, but they invariably resulted in an Earth only a few thousand years old.

By the late 18th century, some naturalists had begun to look closely at the ancient rocks of the Earth.

Second, the rock or mineral must not lose or gain either potassium or argon from the time of its formation to the time of analysis.

By many experiments over the past three decades, geologists have learned which types of rocks and minerals meet these requirements and which do not.Some of the methods have internal checks, so that the data themselves provide good evidence of reliability or lack thereof.Commonly, a radiometric age is checked by other evidence, such as the relative order of rock units as observed in the field, age measurements based on other decay schemes, or ages on several samples from the same rock unit.Lord Kelvin and Clarence King calculated the length of time required for the Earth to cool from a white-hot liquid state; they eventually settled on 24 million years.James Joly calculated that the Earth’s age was 89 million years on the basis of the time required for salt to accumulate in the oceans.The main point is that the ages of rock formations are rarely based on a single, isolated age measurement.

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