Coexisting divergent and convergent plate boundary assemblages indicate plate tectonics in the Neoarchean

Abstract

The coexistence of divergent (spreading ridge) and convergent (subduction zone) plate boundaries at which lithosphere is respectively generated and destroyed is the hallmark of plate tectonics. Here, we document temporally- and spatially-associated Neoarchean (2.55–2.51 Ga) rock assemblages with mid-ocean ridge and supra-subduction-zone origins from the Angou Complex, southern North China Craton. These assemblages record seafloor spreading and contemporaneous subduction initiation and mature arc magmatism, respectively, analogous to modern divergent and convergent plate boundary processes. Our results provide direct evidence for lateral plate motions in the late Neoarchean, and arguably the operation of plate tectonics, albeit with warmer than average Phanerozoic subduction geotherms. Further, we surmise that plate tectonic processes played an important role in shaping Earth’s surficial environments during the Neoarchean and Paleoproterozoic.

Secular Changes in the Occurrence of Subduction During the Archean

“…Our results indicate that arc basalts in the training data set record T P of ∼1160–1500°C, similar to those of Archean arc‐type basalts, although there is a limited occurrence (<2%) of Archean arc‐type basalts with T P exceeding 1500°C (Figure S7 in Supporting Information ). This finding aligns with the observation that Archean arc‐type basalts (∼2.55–2.51 Ga) from the Angou Complex in the southern region of the North China Craton have T P values comparable to those of Izu‐Bonin‐Mariana arc basalts (B. Huang et al., 2022). At least, the Archean arc‐type basalts identified by our model should be comparable to modern arc‐type basalts with T P of ∼1160–1500°C, suggesting that modern‐style subduction occurred during the Archean (see Section 4.5).…”

“…(b) Step changes of Ba contents in tonalite‐trondhjemite‐granodiorite (TTG) suites. Positive shifts of the Ba contents of TTG suites have been taken as indicators of subduction (B. Huang et al., 2022; G. Huang et al., 2022). (c) The relative proportion of juvenile continental crust estimated from the Nd isotopic compositions and Nb model ages of sedimentary rocks (Garçon, 2021).…”

Secular Evolution of Continents and the Earth System

“…The occurrence of large-scale, focused regions of lithospheric extension must be compensated by zones of concurrent compression, and vice versa (cf., B. Huang et al, 2022;Cawood et al, 2018). Thus, it is perhaps not surprising that passive margins and foreland basins both appear at similar times in the geological archive.…”

“…The oldest preserved large‐scale passive margin and foreland basins recognized in the geological record are of the order of 3 Ga and their formation requires lateral motion of lithosphere through extension and compression, respectively (Bhattacharjee et al., 2021; Bradley, 2008; Camiré & Burg, 1993; Catuneanu, 2001; De, 2021; Hofmann et al., 2001; Mueller et al., 2005). The occurrence of large‐scale, focused regions of lithospheric extension must be compensated by zones of concurrent compression, and vice versa (cf., B. Huang et al., 2022; Cawood et al., 2018). Thus, it is perhaps not surprising that passive margins and foreland basins both appear at similar times in the geological archive.…”

Mantle potential temperature and felsic continental crust control the initiation and cessation of plate tectonics

“…The error bars denote the standard deviations. The notable milestones in the Earth's evolution are denoted by the grey bars, including pivotal geological events such as the emergence of the North China Craton (NCC) passive margin 59 , the epochal great oxidation event 91 , uctuations in alkali magmatism 72 , instances of low dT/dP metamorphism 5,33 , and the…”