Early Earth formation and evolution

The extensive early Archean rock records preserved in southwest Greenland and western Australia carry a wealth of information on the formation of Earth's early chemical domains, the age and composition of the oldest continents and the character of the early atmosphere and hydrosphere.  Although these rocks range from 3.6 - 3.9 billion years old, the various isotopic signatures preserved in these rocks record events occurring in the first 500 million years of Earth.

This is the time period when Earth made the transition from a rapidly accreting ball of gas and dust to differentiated planet with a metallic core, silicate mantle and crust and likely some form of proto plate tectonics. Determining the processes that created Earth's chemical architecture are necessary for understanding the present day interactions between crust, mantle, hydrosphere and atmosphere in our intricately linked Earth System, as well a providing a significant benchmark for understanding planet formation.

A highlight of recent work has been the discovery of the signatures of extinct nuclides in our 3.8 billion year old rocks from West Greenland.  These isotopic variations, which originated from the decay of nuclides present in the Earth shortly after solar system formation, but now have totally decayed away, provide some of the strongest evidence for very early formation (at about 4.5 billion years ago) of Earth's major chemical domains.