Isotopic age dating patterson
Eleven years later, Boltwood had pushed the Earth's age past 2000 million years, based on the first U/Pb chemical dating results.
In 1896 the Earth was only 40 million years old according to Lord Kelvin.
Tilton Clair Patterson was an energetic, innovative, determined scientist whose pioneering work stretched across an unusual number of sub-disciplines, including archeology, meteorology, oceanography, and environmental science—besides chemistry and geology.
He is best known for his determination of the age of the Earth.
That was the goal when Patterson began his dissertation project, however attaining it was to take considerably longer than we imagined at the time.
None of the modern techniques, such as laminar flow filtered air, sub-boiling distillation of liquid reagents, and Teflon containers were available in those days. Alpha counting was used as a measure of the uranium and thorium content; lead, which was assumed to be entirely radiogenic (produced by the decay of uranium and thorium), was determined by emission spectroscopy.In spite of those handicaps, Patterson was able to attain processing blanks of circa 0.1 microgram, a very impressive achievement at the time, but now approximately equal to the total amount of sample lead commonly used for isotope analyses. Despite several obvious disadvantages, the method seemed to give reasonable dates on many rocks.