Paleomagnetic evidence for modern-like plate motion velocities at 3.2 Ga

Abstract

The mode and rates of tectonic processes and lithospheric growth during the Archean [4.0 to 2.5 billion years (Ga) ago] are subjects of considerable debate. Paleomagnetism may contribute to the discussion by quantifying past plate velocities. We report a paleomagnetic pole for the ~3180 million year (Ma) old Honeyeater Basalt of the East Pilbara Craton, Western Australia, supported by a positive fold test and micromagnetic imaging. Comparison of the 44°±15° Honeyeater Basalt paleolatitude with previously reported paleolatitudes requires that the average latitudinal drift rate of the East Pilbara was ≥2.5 cm/year during the ~170 Ma preceding 3180 Ma ago, a velocity comparable with those of modern plates. This result is the earliest unambiguous evidence yet uncovered for long-range lithospheric motion. Assuming this motion is due primarily to plate motion instead of true polar wander, the result is consistent with uniformitarian or episodic tectonic processes in place by 3.2 Ga ago.

The Evolution of the Continental Crust and the Onset of Plate Tectonics

“…The oldest supercontinent is late Archean in age, and palaeomagnetic data from the Kaapvaal and Pilbara cratons for the interval 2780-2710 Ma and from the Superior, Kaapvaal and Kola-Karelia cratons for 2700-2440 Ma suggest significant relative movements (Cawood et al, 2018). Brenner et al (2020) concluded that their new palaeomagnetic pole data from 3.18 Ga basalt in the East Pilbara required an average latitudinal drift of >2.5 cm/year for the 170 Ma preceding 3.18 Ga, a velocity comparable with those of modern plates.…”

Tectonics of the Isua Supracrustal Belt 2: Microstructures Reveal Distributed Strain in the Absence of Major Fault Structures

“…3.2–2.5 Ga onset of some form of subduction tectonics that was either episodic or continuous. This work includes isotopic (e.g., Naeraa et al., 2012), geochemical (e.g., M. Tang et al., 2016), petrological (e.g., Brown & Johnson, 2018), geological (e.g., Pease et al., 2008), geochronologic (e.g., Condie & Puetz, 2019), and paleomagnetic (Brenner et al., 2020) studies supporting the onset of plate tectonics during the Meso and/or Neoarchean, alongside numerical modeling explorations and reconstructions suggesting >3.2 Ga operation of hot stagnant‐lid tectonics (Johnson et al., 2017; Moore & Webb, 2013). As such, it can be argued that the scientific community now approaches a consensus concerning when plate tectonics initiated, which would allow a stronger focus on addressing how and why this process occurred.…”

Estimation of Secular Change in the Size of Continents for Understanding Early Crustal Development

“…A recent paleomagnetism study of the Honeyeater Basalt in the East Pilbara Craton suggests a modern plate motion velocity of ≥2.5 cm/year between ca. 3.4-3.2 Ga (Brenner et al, 2020). Conversely, plate subduction before ca.…”