Past on Parade: This geologist got the lead out

Bill Bryson, in his "A Short History of Nearly Everything," saysof Claire "Pat" Patterson: "A good case could be made that he wasthe most influential geologist of the twentieth century."

Patterson was born in Iowa and, with an early interest inchemistry, went to Grinnell College. After a further degree at theUniversity of Iowa, he worked on the Manhattan Project at theUniversity of Chicago and then at Oak Ridge.

He returned to Chicago for his doctorate under the direction ofHarrison Brown. Brown was a great idea man and skilled at raisingmoney. He suggested that Patterson work on the age of rocks, usingan analysis of lead isotopes that had decayed from uranium.

The project continued after they both came to Caltech.

Patterson found so much contamination from lead everywhere thathe had to build a sterile clean lab for the work. Out of that, andanalysis of meteorites, Patterson came up with 4.55 billion yearsfor the age of the earth, a figure that has pretty much stayedvalid.

Patterson continued his research, trying to find the base levelof lead on earth before contamination. He looked at cores bored fromarctic ice, the amount of lead in the oceans and the oceansediments, and lead in ancient skeletons.

He was able to show an increase in lead from human activities anda large increase after tetraethyl lead began to be used as anadditive in gasoline.

Tetraethyl lead is extremely poisonous, and lead in people isinjurious to the nervous system.

When his work was published, his funding from oil companies wasstopped and attempts were made to shut down his work.

He testified before Congress and continued his campaign againsttetraethyl lead in gasoline and also against lead soldering of tinfood cans. The automobile industry finally gave in, and whencatalytic converters were added to cars, that was pretty much theend of tetraethyl lead in gasoline. Also, food cans are no longersealed with lead solder.

Patterson retired from Caltech as professor of geochemistry,emeritus. The Caltech Archives has placed on the Internet atranscript of an oral interview made in 1995, nine months beforePatterson's death, which tells of his life and work in fascinatingdetail.

Sid Gally is a Pasadena Museum of History volunteer