Rubidium 87 radioactive dating
Rubidium 87 radioactive dating - 10025 christian dating site credit card payment
The points will move left as the amount of rubidium decreases and up as the amount of Sr-87 increases.The slope of the isochron line gives the age of the rock.
If the sample had 100 atoms of each isotope, we could assume that 70 of the Sr-87 atoms were primordial and 30 were produced by the decay of Rb-87.Now if the two isotopes of strontium were both primordial, they would plot on a horizontal line, regardless of rubidium content.In samples that contain rubidium, the points will move left and up as the rock ages.Rubidium is a soft, silvery-white metallic element of the alkali metal group, with a standard atomic weight of 85.4678.Elemental rubidium is highly reactive, with properties similar to those of other alkali metals, including rapid oxidation in air.Where the isochron crosses the vertical axis corresponds to a hypothetical sample with no rubidium at all.
In other words, the Sr-87/Sr-86 ratio there is the content the rock had before any rubidum decayed.
Rubidium has a 1 charge as a cation versus the 2 or strontium, and a larger ionic radius.
So the two elements are not entirely chemically compatible.
Early attempts at Rubidium-Strontium dating made use of the fact that the Sr-87/Sr-86 ratio in rubidium-poor samples was about 0.7.
Since these samples were poor in rubidium, it could be assumed that the primordial ratio of Sr-87 to Sr-86 was 0.7.
Rubidium's compounds have various chemical and electronic applications.