How potassium argon dating works
Sr) was the first widely used dating system that utilized the isochron method.
Well-preserved, unweathered rocks that crystallized rapidly and have not been subjected to major reheating events are most likely to give valid isochrons.
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.
The samples are crushed and homogenized to produce a fine representative rock powder from which a fraction of a gram is withdrawn and dissolved in the presence of appropriate isotopic traces, or spikes.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.