Building Mesoarchaean crust upon Eoarchaean roots: the Akia Terrane, West Greenland

Research output: Contribution to journalJournal articleResearchpeer-review


  • N. J. Gardiner
  • C. L. Kirkland
  • J. Hollis
  • Szilas, Kristoffer
  • A. Steenfelt
  • C. Yakymchuk
  • H. Heide-Jørgensen
Constraining the source, genesis, and evolution of Archaean felsic crust is key to understanding the growth and stabilization of cratons. The Akia Terrane, part of the North Atlantic Craton, West Greenland, is comprised of Meso-to-Neoarchaean orthogneiss, with associated supracrustal rocks. We report zircon U--Pb and Lu--Hf isotope data, and whole-rock geochemistry, from samples of gneiss and supracrustals from the northern Akia Terrane, including from the Finnefjeld Orthogneiss Complex, which has recently been interpreted as an impact structure. Isotope data record two major episodes of continental crust production at ca. 3.2 and 3.0 Ga. Minor ca. 2.7 and 2.5 Ga magmatic events have more evolved $Hf, interpreted as reworking of existing crust perhaps linked to terrane assembly. Felsic rocks from the Finnefjeld Orthogneiss Complex were derived from the same source at the same time as the surrounding tonalites, but from shallower melting, requiring any bolide-driven melting event to have occurred almost simultaneously alongside the production of the surrounding crust. A simpler alternative has the Finnefjeld Complex and surrounding tonalite representing the coeval genesis of evolved crust over a substantial lithospheric depth. Hafnium isotope data from the two major Mesoarchaean crust-forming episodes record a contribution from older mafic Eoarchaean crust. Invoking the involvement of an Eoarchaean root in the growth of younger Mesoarchaean crust puts important constraints on geodynamic models of the formation of the discrete terranes that ultimately assembled to form Earth's cratons.
Original languageEnglish
Article number20
JournalContributions to Mineralogy and Petrology
Issue number3
Number of pages19
Publication statusPublished - 2019

Number of downloads are based on statistics from Google Scholar and

No data available

ID: 213930102