When did plate tectonics begin? Evidence from the geologic record

Abstract:

Modern-style plate tectonics can be tracked into the geologic past with petrotectonic assemblages and other plate-tectonic indicators. These indicators suggest that modern plate tectonics were operational, at least in some places on the planet, by 3.0 Ga, or even earlier, and that they became widespread by 2.7 Ga. The scarcity of complete ophiolites before 1 Ga may be explained by thicker oceanic crust and preservation of only the upper, basaltic unit. The apparent absence of blueschists and ultrahigh-pressure meta-morphic rocks before ca. 1 Ga may reflect steeper subduction geotherms and slower rates of uplift at convergent margins. It is unlikely that plate tectonics began on Earth as a single global "event" at a distinct time, but rather it is probable that it began locally and progressively became more widespread from the early to the late Archean. © 2008 The Geological Society of America.

Año de publicación:

2008

Keywords:

• Plate tectonics
• Mantle recycling
• Plate tectonic assemblages
• Archean tectonics

Fuente:

scopus