Paleomagnetic evidence for Neoarchean plate mobilism

Area of Science:

• Geosciences
• Paleomagnetism
• Tectonics

Background:

• The initiation of plate tectonics on Earth is highly debated, with proposed start times varying widely.
• Paleomagnetic data is crucial for understanding large-scale lateral movements of Earth's crustal blocks.
• Previous paleomagnetic evidence constrained the oldest relative horizontal motion to 2.7–2.17 billion years ago.

Purpose of the Study:

• To investigate the timing of the earliest plate tectonics using paleomagnetic data.
• To determine the timing of assembly and juxtaposition of the Wyoming and Superior cratons.
• To provide evidence for relative horizontal motion between crustal blocks in the Neoarchean.

Main Methods:

• Acquisition of a paleomagnetic pole from the Wyoming craton.
• Analysis of apparent polar wander paths for the Wyoming and Superior cratons.
• Integration of paleomagnetic results with tectonostratigraphic data and geological proxies.

Main Results:

• A robust paleomagnetic pole dated to approximately 2.48 billion years ago was obtained from the Wyoming craton.
• The Wyoming and Superior cratons likely assembled between 2.7–2.5 billion years ago and remained juxtaposed until 2.17 billion years ago.
• Collision between the Wyoming and Superior cratons is suggested around 2.6 billion years ago, supported by geological evidence.

Conclusions:

• The study provides strong evidence for significant relative horizontal motion between crustal blocks during the Neoarchean.
• The findings suggest that plate mobilism was active on Earth prior to 2.5 billion years ago.
• This research contributes to resolving the controversy surrounding the initiation of plate tectonics.