When did plate tectonics begin?

The plate tectonic paradigm has been the dominant model for understanding the solid Earth for over 40 years. However, although the model is hugely successful, there is still great uncertainty as to when the plate tectonic process began. Two recent papers have highlighted this difficulty by proposing two very different start times for plate tectonics. One model argues that plate tectonic processes took over from an earlier (unspecified) tectonic regime in a hotter, younger Earth at 1.0 Ga, whereas the other proposes a much earlier start at 4.4–4.5 Ga, and within a 100 Ma of planetary accretion. This feature discusses the evidence for the early and late start hypotheses and argues for a middle position in which plate tectonic processes began during the Archaean (>2.5 Ga ago).