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 uranium–lead dating method into lead–lead dating.

Patterson graduated from high school in 1939, at the age of 16.

Patterson first encountered lead contamination in the late 1940s as a graduate student at the University of Chicago.

His work on this subject led to a total re-evaluation of the growth in industrial lead concentrations in the atmosphere and the human body, and his subsequent activism was seminal in the banning of tetraethyllead in gasoline and lead solder in food cans.

He was born in Mitchellville, Iowa.

His father was a mail carrier and his mother was a member of the school board; Patterson had one brother, Paul, and one sister, Patricia.

From a young age he was encouraged by his family to pursue his intellectual curiosity.

He attended Grinnell College—close enough that Patterson would hitchhike home to do laundry —and graduated with a degree in chemistry in 1943.

There, he met his future wife, Lorna (Laurie) McCleary.

For graduate school, they both attended the University of Iowa, where he was awarded an M.A. in molecular spectroscopy.

He also married Lorna McCleary just before leaving the University of Iowa in 1944.

Both were then sent to work on the Manhattan Project as civilians, first at the University of Chicago and then at Oak Ridge, Tennessee, where he encountered mass spectrometry.

After World War II, the Pattersons returned to Chicago, where Laurie took a research job as an infrared spectroscopist to support Patterson while he studied for his Ph.D. at the University of Chicago under Harrison Brown.

While studying at an old laboratory, Patterson was able to make discoveries involving the lead that he ended up studying later in his life.

He made several different experiments which led to shocking results for the time period involving the lead.

As Patterson and Tilton began their work in 1948, Patterson quickly became aware that his lead samples were being contaminated.

They knew the age of the igneous rock from which the zircon came, and Tilton's uranium measurements aligned with what should be in a zircon at that particular age, but Patterson's data always was skewed with too much lead.

After six years, the team published a paper on methods of determining the ages of zircon crystals and Patterson earned his Ph.D., but they were no closer in determining the age of the Earth.

Brown was able to receive a grant from the United States Atomic Energy Commission to continue work on dating the Earth, but more importantly, to commission a new mass spectrometer in Pasadena, California at Caltech.

After a postdoctoral year at Chicago, Patterson moved with Brown to the Division of Geology (later the Division of Geological and Planetary Sciences) at the California Institute of Technology in 1952, as founding members of its geochemistry program.

Patterson remained at Caltech for the rest of his life.

He and Laurie had four children.

Patterson returned to the University of Chicago to work under his research adviser Harrison Brown.

Brown, knowing about Patterson's experience with mass spectrometry, teamed him up with George Tilton to do geological aging on zircons.

Zircons are extremely useful for dating since, when they are formed, they possess tiny imperfections of uranium, but no lead.

Therefore, if any lead is present in the zircon, it must come from the decay of uranium.

This process is known as U-Pb dating.

The job of the team was to measure the concentration and isotopic compositions of the elements inside the zircon.

Tilton was to measure the uranium and Patterson, the amount and type of lead.

The goal for Patterson was to figure out the composition of the primordial lead in the Earth.

In doing so, it would be possible to figure out the age of the Earth and, in turn, of the solar system by using the same techniques on meteorites.

In 1953, Brown brought Patterson along with him to Caltech, where Patterson was able to build his own lab from scratch.

In it, he secured all points of entry for air and other contaminants.

Patterson also acid cleaned all apparatuses and even distilled all of his chemicals shipped to him.

In essence, he created one of the first clean rooms ever, in order to prevent lead contamination of his data.

He then was able to finish his work with the Canyon Diablo meteorite in 1953.

By using lead isotopic data from the Canyon Diablo meteorite, he calculated an age for the Earth of 4.55 billion years, which was a figure far more accurate than those that existed at the time, and one that has remained largely unchallenged since 1956.