Oldest Earth rock

As rocks are constantly undergoing processes such as weathering and are subject to tectonic/volcanic activity, very few survive from the earliest period of Earth's formation. Samples of bedrock from the Nuvvuagittuq Greenstone Belt the eastern shore of Hudson Bay in north-eastern Canada have been dated to approximately 4.16–4.2 billion years old, which means they currently represent what is the oldest known intact planetary crust on Earth, dating to the Hadean Eon, the first geological period. Various studies have debated the precise age, varying from 3.75 billion years up to 4.3 billion years.

The approximate age of 4.16–4.2 billion years was determined using samarium-neodymium isotope dating techniques as outlined in a study published in the journal Science on 26 June 2025.

There are even older mineral fragments that have been uncovered. Tiny, diamond-like crystals of zircon (ZrSiO4) from the Jack Hills in Western Australia have been dated at 4.374 billion years (±0.006 billion years/6 million years), which means that these zircons formed only around 160 million years after Earth itself was formed.

Rocks that have fallen on Earth from space can also exceed the Nuvvuagittuq Greenstone Belt crust in terms of age. The oldest igneous (aka magmatic) rock discovered on Earth is a c. 4.565-billion-year-old meteorite that was found in the desert of south-west Algeria in May 2020. Named Erg Chech 002 (abbreviated to EC 002), it is a stony meteorite known as an achondrite, formed from a type of volcanic rock known as andesite. The meteorite is marginally older than Earth, which formed c. 4.5 billion years ago. Scientists believe that it may have originated in the crust of a protoplanet – a celestial body born just a few million years after the Solar System itself coalesced.