Chinese scholars and overseas collaborators have made progress in the study of the tectonic pattern of the New Archean plate

Fig.
1 Phase equilibrium-trace element simulation reveals geothermal gradients in subduction zones (left) and tectonic patterns (right)

Fig.
2 Conceptual model of plate tectonic process at the Archean-Proterozoic intersection and its influence on the solid-epibiosphere layer of the Earth

With the support of the National Natural Science Foundation of China (grant numbers: 42102244, 41890834 and 4191144020), the team of Professor Tim Kosky, associate researcher Huang Bo of China University of Geosciences (Wuhan), cooperated with researchers from Australia and Canada to make new progress
in the operation characteristics and style definition of plate tectonics in the late Archean period 。 The results, titled "Coexisting divergent and convergent plate boundary assemblages indicate plate tectonics in the Neoarchean," were published online in Nature Communications on October 28, 2022 Communications
).
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Plate tectonics promote the interaction between the deep Earth and the surface sphere, fundamentally shaping the Earth's environment and habitability
.
However, how the occurrence time of plate tectonics and its pattern evolve with the gradual cooling of the mantle and how it affects the surface sphere layer is one of the frontier and hot scientific issues that have been controversial for a long time in the field of
solid earth science 。 In order to solve this problem, the research team carried out comprehensive geological research on the late Archean (2.
55-2.
51 billion years ago) of the southern margin of the North China craton, and identified the mid-ocean ridge-passive continental margin and the upper coiled island arc/pre-arc rock tectonic units with temporal and spatial associations, which were formed at discrete and convergent plate boundaries, respectively, indicating that there were plate relative motion processes such as seafloor expansion, subduction initiation, subduction proliferation, island arc magma and arc-land collision, which provided new geological evidence for the start of plate tectonics
。

In addition, based on geochemical characteristics and thermodynamic-trace element forward simulation, a genesis model of TTG magma formed by partial melting of subduction plates was proposed, and the geothermal gradient of the subduction zone was limited to 440~470°C/GPa, which was consistent with the warm (hot) subduction zone of the Phanerozoic (Figure 1).

By comparing the subduction zone and orogenic belt patterns between the late Archean and the Phanerozoic, the researchers believe that the plate tectonic process at the end of the Archean period has certain similarities
with the Phanerozoic.
The team proposed a conceptual model to illustrate the impact that the widely developed plate tectonic processes of the Neo-Archean might have had at the Archean-Proterozoic intersection and subsequent lithosphere, oceanosphere, atmosphere, and biosphere evolution (Figure 2).

Discrete and convergent plate boundary geological processes contributed to major geological, metallogenic and environmental evolutions during this period, such as mantle heat loss, vertical and lateral growth of continental crust, surfacing of continental crust, BIF mineralization, arc-continental collision orogeny, continental crust weathering and denudation and carbon dioxide depletion, increased marine nutrient input and primary productivity, earth oxygenation (GOE) and first snowball earth formation
.

This study not only shows that plate tectonics started at least in the Neo-Archean, but also provides new ideas
for defining plate tectonic patterns and understanding plate boundary processes and their resource and environmental effects in this period.