How much of Earth's geological history was preordained in the Hadean? A review of the evidence

In this paper, we take up James Hutton's challenge from 1785 to investigate if, after 240 years, we can now identify any ‘ vestige of a beginning ’. During Hutton's time, a debate raged as to the relative role played by uniformitarianism versus catastrophism in shaping Earth's evolution. Today, we realise that both played a part, with a likely catastrophic beginning, followed by extensive periods of relatively steady-state, mantle-controlled cyclicity, but punctuated by cataclysmic events that had a profound effect on the evolution of life. Multiple isotopic systems define the ‘beginning’, i.e., the age of the solar system. But whether Earth's ‘beginning’ started with a Mars-sized impactor soon after accretion remains controversial. Significantly, zircon has provided a ‘footprint’ of events in the Hadean eon, extending back to within ∼170 Myr of solar system formation - a true ‘ vestige of a beginning ’. Evidence gleaned from zircon through major advances in analytical techniques has enabled us to gain a wealth of knowledge about what happened in the first 500 Myr of Earth history even though no rocks were preserved, indicating a likely continuity in certain key Earth processes from the Hadean to the present time.