The age of a rock in years is called its absolute age. Geologists find absolute ages by measuring the amount of certain radioactive elements in the rock. When rocks are formed, small amounts of radioactive elements usually get included. As the rock ages, more and more of the uranium changes into lead.

How is rock age defined?

The age of a rock is determined by stratigraphy, a branch in geology which studies the chronology of events and changes, along with the development of organisms, which have determined the development of the Earth from when it became an independent spatial body until today.

Why is the age of rocks important?

Gaining estimates of ages of rocks is crucial for establishing not only the history of geological events but also for determining the rates of geological processes. It is possible to establish the relative order of events in some rocks.

What is the oldest rocks on Earth?

The oldest zircons, from grains in Western Australia, are about 4.36 billion years old. The Nuvvuagittuq rocks are the oldest whole rocks found so far though, said geologist Richard Carlson of the Carnegie Institution, who analyzed the rocks with Jonathan ONeil, a Ph. D. student at McGill University in Montreal.

What was the first rock on Earth?

Acasta Gneiss In 1999, the oldest known rock on Earth was dated to 4.031 ±0.003 billion years, and is part of the Acasta Gneiss of the Slave craton in northwestern Canada.

How old is our world?

4.543 billion years Earth/Age