Strontium dating chilli and lasse dating

In older sequences diagenetic alteration combined with greater uncertainties in estimating absolute ages due to lack of overlap between other geochronometers (for example U-Th) leads to greater uncertainties in the exact shape of the Sr isotope seawater curve.Radiometric dating is a means of determining the "age" of a mineral specimen by determining the relative amounts present of certain radioactive elements.

strontium dating-23

For example, uranium-238 is an isotope of uranium-235, because it has 3 more neutrons in the nucleus.

It has the same number of protons, otherwise it wouldn't be uranium.

This then causes orthoclase and biotite, both K rich minerals into which Rb can substitute, to precipitate.

The resulting Rb-Sr ratios and Rb and Sr abundances of both the whole rocks and their component minerals will be markedly different.

If the initial amount of Sr is known or can be extrapolated, the age can be determined by measurement of the Rb and Sr concentrations and the Sr ratio.

The dates indicate the true age of the minerals only if the rocks have not been subsequently altered.

The slope of the line dictates the age of the sample.

Rb-Sr dating relies on correctly measuring the Rb-Sr ratio of a mineral or whole rock sample, plus accurately deriving an accurate One of the major drawbacks (and, conversely, the most important use) of utilizing Rb and Sr to derive a radiometric date is their relative mobility, especially in hydrothermal fluids.

Rb and Sr are relatively mobile alkaline elements and as such are relatively easily moved around by the hot, often carbonated hydrothermal fluids present during metamorphism or magmatism.

Tags: , ,