Dating rocks

1907

Dating rocks

The book of science

Tom Sharp

Bertram Boltwood geology

Dating rocks

Zircon clocks

A beginning

The Jhomon Sugi tree of Yakushima in Japan, dated by counting tree rings or by radiocarbon dating, could be 7,200 years old. This is 1/625,000th of the duration of the earth.

See also in The book of science:

Readings on wikipedia: