Oldest rocks — Science Information, July 21, 1973
Till just lately, Greenland possessed the oldest recognized rocks on the planet. They date again 3.7 billion years (SN: 12/9/72, p. 374). Now granite and crystalline schist specimens … recommend that the Antarctic Continent is older. These specimens date again 4 billion years.
Replace:
At about 4.3 billion years outdated, bedrock in northeastern Canada presently holds the title of oldest recognized rock on Earth (SN: 4/15/17, p. 8). In Western Australia, scientists have discovered zircon crystals in bedrock which might be even older, courting to about 4.4 billion years in the past. For comparability, Earth is barely about 4.5 billion years outdated.
Since these historical supplies protect details about early Earth, they’ve fueled ongoing debates about when and how Earth’s crust fashioned, when plate tectonics began and even when life on the planet first arose (SN: 2/23/14; SN: 5/2/22; SN: 10/19/15). Further clues that would assist resolve the debates would possibly lie on the moon. Lunar samples collected by Apollo 14 astronauts include 4-billion-year-old zircons that will have been delivered by way of an Earth meteor, scientists reported in 2019.