Active plate tectonics on early Earth: insights from the New Zealand plate boundary zone

19 March 2026 - 19 March 2026

Region(s): Nationwide, Wellington

Type(s): presentations

Come along or Zoom in, to this free GSNZ Wellington branch meeting, presented by Dr Simon Lamb.

Plate tectonics has played a major role in the Earth’s evolution, both in the cooling of the planetary interior, and, it is widely argued, the maintenance of liquid water and life at the surface. But was the Earth always like this? The answer to this question is most likely to lie in relicts of the early Earth’s surface, preserved in Archean greenstone belts and found in almost all the cratons.

In this free talk, Simon Lamb will compare field relations in the 3.5 – 3.2 Ga Barberton Greenstone Belt in South Africa and Eswatini with the active New Zealand subducting plate-boundary zone. He will show that there are remarkable similarities in structure and stratigraphy, with many of the distinctive features of convergent plate margins. Simon will argue that the simplest explanation is that plate tectonics was fully active prior to 3.2 Ga, in the early Archean (Paleoarchean), generating great earthquakes on the subduction megathrust and growth folds and major low angle thrusts in the overlying accretionary prism and subsequent continental collision.

Oceania in the SW Pacific may provide us with the closest modern example of the surface of the Paleoarchean Earth, forming a water world with active volcanoes, back-arc spreading and small continental landmasses along a subducting plate boundary with local continental collision. In fact, the eruption of boninites here in the back-arc region may be a direct analogy for the typical komatiitic volcanism in the early Earth. The explosive eruption of Hunga Volcano near Tonga in 2022 could even provide clues to the origin of life, suggesting that life was born out of the extreme violence of plate tectonics, a far cry from Darwin’s benign and warm little pond.

Location: GBLT1, Old Government Buildings, Pipitea Campus, Victoria University of Wellington, Wellington.

This talk will be lived streamed but not recorded: https://vuw.zoom.us/j/98603409189

For more information: https://gsnz.org.nz/gsnz-events/ViewEvent/470.