Titanium isotopes constrain a magmatic transition at the Hadean-Archean boundary in the Acasta Gneiss Complex

Sarah M. Aarons, Jesse R. Reimink, Nicolas D. Greber, Andy W. Heard, Zhe Zhang, Nicolas Dauphas

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Plate subduction greatly influences the physical and chemical characteristics of Earth's surface and deep interior, yet the timing of its initiation is debated because of the paucity of exposed rocks from Earth's early history. We show that the titanium isotopic composition of orthogneisses from the Acasta Gneiss Complex spanning the Hadean to Eoarchean transition falls on two distinct magmatic differentiation trends. Hadean tonalitic gneisses show titanium isotopic compositions comparable to modern evolved tholeiitic magmas, formed by differentiation of dry parental magmas in plume settings. Younger Eoarchean granitoid gneisses have titanium isotopic compositions comparable to modern calc-alkaline magmas produced in convergent arcs. Our data therefore document a shift from tholeiitic- to calc-alkaline-style magmatism between 4.02 and 3.75 billion years (Ga) in the Slave craton.

Original languageEnglish (US)
Article numbereabc9959
JournalScience Advances
Volume6
Issue number50
DOIs
StatePublished - Dec 9 2020

All Science Journal Classification (ASJC) codes

  • General

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