Rb sr dating exercise

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The samples are crushed and homogenized to produce a fine representative rock powder from which a fraction of a gram is withdrawn and dissolved in the presence of appropriate isotopic traces, or spikes.

Strontium and rubidium are extracted and loaded into the mass spectrometer, and the values appropriate to the , the data are examined to assess how well they fit the required straight line.

On the other hand, meteorites that have spent most of their time in the deep freeze of outer space can provide ideal samples.

Potassium-bearing minerals including several varieties of mica, are ideal for rubidium–strontium dating as they have abundant parent rubidium and a low abundance of initial strontium.

Such scatter would constitute a geologic component, indicating that one or more of the underlying assumptions has been violated and that the age indicated is probably not valid.Weathering is a disturbing influence, as is leaching or exchange by hot crustal fluids, since many secondary minerals contain rubidium.Volcanic rocks are most susceptible to such changes because their minerals are fine-grained and unstable glass may be present.Sr) was the first widely used dating system that utilized the isochron method.Rubidium is a relatively abundant trace element in Earth’s crust and can be found in many common rock-forming minerals in which it substitutes for the major element potassium.This situation is easily visualized on an isochron diagram, where a series of rocks plots on a steep line showing the primary age, but the minerals in each rock plot on a series of parallel lines that indicate the time since the heating event.

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