Clair Cameron Patterson

Clair Cameron Patterson (June 2, 1922 – December 5, 1995) was an American geochemist. Born in Mitchellville, Iowa, Patterson graduated from Grinnell College. He later received his Ph.D. from the University of Chicago and spent his entire professional career at the California Institute of Technology (Caltech).

In collaboration with George Tilton, Patterson developed the lead–lead dating method from the established procedures for uranium–lead dating. By using lead isotopic data from the Canyon Diablo meteorite, he calculated an age for the Earth of 4.55 billion years, a figure far more accurate than estimates existing at the time, and one that has remained largely unchallenged since 1956.

Patterson first encountered ubiquitous lead contamination in the late 1940s as a graduate student at the University of Chicago. Later, his work on this subject led to a total (US and worldwide) re-evaluation of the unregulated growth of concentrations of industrial lead in the atmosphere and in the human body. His activism about this problem proved seminal in the banning of "leaded gasoline", as well as "leaded solder" in food cans. Provided by Wikipedia