Archean geodynamics

similar to or different from modern geodynamics?

Kent C. Condie*, Keith Benn

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingChapter

38 Citations (Scopus)

Abstract

There is a wealth of geologic, geochemical, structural, volcanologic, and sedi-mentologic data that are consistent with Archean plate tectonics, especially after 3.0 Ga. Neither the eruption of submarine basalts onto thinned continental crust nor the existence of ductile or viscous diapirism precludes the existence of plate tectonics during the Archean. Some "missing indicators" of plate tectonics are found in Archean terranes (probable oceanic crust, melange, possible passive margin sequences, boninite), whereas the absence of others (such as blueschists) can be explained by a higher Archean mantle geotherm. Bimodal magmatism is not limited to the Archean but occurs in several modern tectonic settings. The relative abundance of komatiites in the Archean reflects hotter Archean mantle and possibly widespread mantle plume activity. Any viable model for Archean geodynamics must accommodate the following 10 constraints: During the Archean, the mantle was hotter than it is today; there are two styles of crustal deformation in the Archean; komatiite is proportionally more abundant in Archean greenstones than in younger greenstones; tonalite-trondhjemite-granodiorite depleted in heavy rare earth elements is more widespread in the Archean than afterwards; thick lithosphere underlies many Archean cratons; portions of the mantle were strongly depleted in large ion lithophile elements during the Archean; many Archean greenstones comprise arc-like rock assemblages; a significant proportion of Archean greenstones contain volcanic rocks with geochemical characteristics similar to modern plume-derived basalts; paleomagnetic data indicate that apparent polar wandering occurred during the Archean; and a large volume of continental crust was produced about 2.7 Ga.

Original languageEnglish
Title of host publicationArchean Geodynamics and Environments
EditorsKeith Benn, Jean-Claude Mareschal, Kent C. Condie
Place of PublicationWashington, D.C.
PublisherAmerican Geophysical Union
Pages47-59
Number of pages13
ISBN (Electronic)9781118666265
ISBN (Print)9780875904290
DOIs
Publication statusPublished - 2006
Externally publishedYes

Publication series

NameGeophysical Monograph Series
PublisherAmerican Geophysical Union
Volume164
ISSN (Print)0065-8448

Keywords

  • Earth-Crust
  • Earth-Mantle
  • Geodynamics
  • Geology, Stratigraphic-Archaean
  • Geology, Structural
  • Plate tectonics

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  • Cite this

    Condie, K. C., & Benn, K. (2006). Archean geodynamics: similar to or different from modern geodynamics? In K. Benn, J-C. Mareschal, & K. C. Condie (Eds.), Archean Geodynamics and Environments (pp. 47-59). (Geophysical Monograph Series; Vol. 164). Washington, D.C.: American Geophysical Union. https://doi.org/10.1029/164GM05