Spatial and temporal control of Archean tectonomagmatic regimes

Eric D. Vandenburg, Oliver Nebel, R. Hugh Smithies, Fabio A. Capitanio, Laura Miller, Peter A. Cawood, Marc Alban Millet, Emilie Bruand, Jean François Moyen, Xueying Wang, Yona Nebel-Jacobsen

Research output: Contribution to journalReview ArticleResearchpeer-review

8 Citations (Scopus)

Abstract

Secular trends in plutonic whole-rock geochemistry pose critical, although non-unique, constraints to early Earth tectonics. Here, we present a large whole-rock geochemical (879 collated samples) dataset for granitoids from the Pilbara Craton, Western Australia, applying it to test the link between secular trends and proposed tectonic mechanisms. We show that the spatio-temporal distribution of granitoid trace element geochemistry is constrained within discrete lithotectonic blocks supporting the reconstruction of its tectonomagmatic evolution. Time-sliced geochemical contour mapping of key petrogenetic ratios indicates the craton underwent rifting ∼3.2 Ga (billion years ago), marking a transition from predominantly sodic magmatism to a broader magmatic compositional spectrum. Our results demonstrate that rift-assisted breakup of proto-cratons is a viable craton growth mechanism. We identify a possible evolutionary sequence beginning with drips and upwellings below a Paleoarchean mafic plateau, which is subsequently dismembered by rifting. These plateau fragments form rigid blocks in the Mesoarchean, between which weaker, thinner crust accommodates minor convergence and divergence manifested as short-lived mobile lid-like features before stabilization. We conclude that these features do not require an active lid, plate tectonic regime.

Original languageEnglish
Article number104417
Number of pages13
JournalEarth-Science Reviews
Volume241
DOIs
Publication statusPublished - Jun 2023

Keywords

  • Continental crust
  • Dripduction
  • Geochemistry
  • Granitoids
  • Pilbara Craton
  • Sluggish lid

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