Oldest rocks — Science Information, July 21, 1973
Till not too long ago, Greenland possessed the oldest identified rocks on the planet. They date again 3.7 billion years (SN: 12/9/72, p. 374). Now granite and crystalline schist specimens … counsel that the Antarctic Continent is older. Those specimens date again 4 billion years.
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At about 4.3 billion years previous, bedrock in northeastern Canada recently holds the name of oldest identified rock on Earth (SN: 4/15/17, p. 8). In Western Australia, scientists have discovered zircon crystals in bedrock which can be even older, courting to about 4.4 billion years in the past. For comparability, Earth is best about 4.5 billion years previous.
Since those historical fabrics keep details about early Earth, they have got fueled ongoing debates about when and how Earth’s crust shaped, when plate tectonics began or even when existence on this planet first arose (SN: 2/23/14; SN: 5/2/22; SN: 10/19/15). Further clues that might lend a hand get to the bottom of the debates would possibly lie at the moon. Lunar samples accumulated through Apollo 14 astronauts include 4-billion-year-old zircons that can had been delivered by way of an Earth meteor, scientists reported in 2019.