3 methods of dating rock

If a number of samples are analyzed and the results are shown to define a straight line within error, then a precise age is defined because this is only possible if each is a closed system and each has the same initial ratio and age.

3 methods of dating rock-353 methods of dating rock-58

Similar studies have shown that the samarium–neodymium (Sm–Nd) parent–daughter pair is more resistant to secondary migration but that, in this instance, sufficient initial spread in the abundance of the parent isotope is difficult to achieve.trace minerals may form, each concentrating certain elements and radioactive trace elements within the rock.

By careful selection, certain minerals that contain little or no daughter element but abundant parent element can be analyzed.

A second advantage of the method relates to the fact that under high-temperature conditions the daughter isotopes may escape from the host minerals.

In this case, a valid age can still be obtained, provided that they remain within the rock.

In some cases the discovery of a rare trace mineral results in a major breakthrough as it allows precise ages to be determined in formerly undatable units.

For example, the mineral those composed primarily of one or more ferromagnesian, dark-coloured minerals).Many radioactive dating methods are based on minute additions of daughter products to a rock or mineral in which a considerable amount of daughter-type isotopes already exists.These isotopes did not come from radioactive decay in the system but rather formed during the original creation of the elements.In this case, it is a big advantage to present the data in a form in which the abundance of both the parent and daughter isotopes are given with respect to the abundance of the initial background daughter.The incremental additions of the daughter type can then be viewed in proportion to the abundance of parent atoms. It has already been shown— In practice, the isochron approach has many inherent advantages.In this case, the slope of the line in potassium–argon (K–Ar) dating, for example, because most minerals do not take argon into their structures initially.

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