A planet in transition

the onset of plate tectonics on Earth between 3 and 2 Ga?

Kent C. Condie*

*Corresponding author for this work

Research output: Contribution to journalArticle

63 Citations (Scopus)
75 Downloads (Pure)

Abstract

Many geological and geochemical changes are recorded on Earth between 3 and 2 Ga. Among the more important of these are the following: (1) increasing proportion of basalts with "arc-like" mantle sources; (2) an increasing abundance of basalts derived from enriched (EM) and depleted (DM) mantle sources; (3) onset of a Great Thermal Divergence in the mantle; (4) a decrease in degree of melting of the mantle; (5) beginning of large lateral plate motions; (6) appearance of eclogite inclusions in diamonds; (7) appearance and rapid increase in frequency of collisional orogens; (8) rapid increase in the production rate of continental crust as recorded by zircon age peaks; (9) appearance of ophiolites in the geologic record, and (10) appearance of global LIP (large igneous province) events some of which correlate with global zircon age peaks. All of these changes may be tied directly or indirectly to cooling of Earth's mantle and corresponding changes in convective style and the strength of the lithosphere, and they may record the gradual onset and propagation of plate tectonics around the planet. To further understand the changes that occurred between 3 and 2 Ga, it is necessary to compare rocks, rock associations, tectonics and geochemistry during and between zircon age peaks. Geochemistry of peak and inter-peak basalts and TTGs needs to be evaluated in terms of geodynamic models that predict the existence of an episodic thermal regime between stagnant-lid and plate tectonic regimes in early planetary evolution.

Original languageEnglish
Pages (from-to)51-60
Number of pages10
JournalGeoscience Frontiers
Volume9
Issue number1
Early online date22 Sep 2016
DOIs
Publication statusPublished - Jan 2018
Externally publishedYes

Bibliographical note

Copyright the Publisher 2016. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Plate tectonics
  • Zircon age peaks
  • Mantle evolution
  • Stagnant lid
  • Continental crust
  • LIP events

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