The origin of Earth’s first continents and the onset of plate tectonics

Research output: Contribution to journalArticlepeer-review

Authors

  • Alan Hastie
  • J. Godfrey Fitton
  • Geoffrey D. Bromiley
  • Ian B. Butler
  • Nicholas W. A. Odling

Colleges, School and Institutes

Abstract

The growth and recycling of continental crust has resulted in the chemical and thermal modification of Earth’s mantle, hydrosphere, atmosphere, and biosphere for ~4.0 b.y. However, knowledge of the protolith that gave rise to the first continents and whether the environment of formation was a subduction zone still remains unknown. Here, tonalite melts are formed in high P-T experiments in which primitive oceanic plateau starting material is used as an analogue for Eoarchean (3.6–4.0 Ga) oceanic crust generated at early spreading centers. The tonalites are produced at 1.6–2.2 GPa and 900–950 °C and are mixed with slab-derived aqueous fluids to generate melts that have compositions identical to that of Eoarchean continental crust. Our data support the idea that the first continents formed at ca. 4 Ga and subsequently, through the subduction and partial melting of ~30–45-km-thick Eoarchean oceanic crust, modified Earth’s mantle and Eoarchean environments and ecosystems.

Details

Original languageEnglish
Pages (from-to)855-858
Number of pages4
JournalGeology
Volume44
Issue number10
Early online date31 Aug 2016
Publication statusPublished - 1 Oct 2016