Extreme δ18O signatures in zircon from the Saglek Block (North Atlantic Craton) document reworking of mature supracrustal rocks as early as 3.5 Ga

Abstract

Research Article| April 25, 2019 Extreme δ18O signatures in zircon from the Saglek Block (North Atlantic Craton) document reworking of mature supracrustal rocks as early as 3.5 Ga Adrien Vezinet; Adrien Vezinet 1Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Emilie Thomassot; Emilie Thomassot 2Centre de Recherches Pétrographiques et Géochimiques, UMR 7358, Université de Lorraine, CNRS, 54500 Vandoeuvre-lès-Nancy, France3Institute for Geochemistry and Petrology, ETH Zürich, Clausiusstrasse 25, 8038 Zurich, Switzerland Search for other works by this author on: GSW Google Scholar D. Graham Pearson; D. Graham Pearson 1Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Richard A. Stern; Richard A. Stern 1Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Yan Luo; Yan Luo 1Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Chiranjeeb Sarkar Chiranjeeb Sarkar 1Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2E3, Canada Search for other works by this author on: GSW Google Scholar Geology (2019) 47 (7): 605–608. https://doi.org/10.1130/G46086.1 Article history received: 04 Feb 2019 rev-recd: 25 Mar 2019 accepted: 27 Mar 2019 first online: 25 Apr 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Adrien Vezinet, Emilie Thomassot, D. Graham Pearson, Richard A. Stern, Yan Luo, Chiranjeeb Sarkar; Extreme δ18O signatures in zircon from the Saglek Block (North Atlantic Craton) document reworking of mature supracrustal rocks as early as 3.5 Ga. Geology 2019;; 47 (7): 605–608. doi: https://doi.org/10.1130/G46086.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract The most ancient rocks in the geological record provide insights into the processes that shaped the evolution and composition of the first continental masses. To better constrain these processes, we made a detailed study of a ca. 3.86 Ga felsic meta-igneous rock from the Eoarchean Saglek Block (North Atlantic Craton) that experienced high-grade metamorphism at ca. 3.5 Ga. Our robust zircon-isotope plus trace-element analyses reveal metamorphic zircon domains with δ18O values up to +9‰ at ca. 3.5 Ga, which are the highest values so far measured in any pre–3.0 Ga zircons, metamorphic or igneous, extracted from unambiguous (meta)igneous host rocks. Such elevated zircon δ18O signatures clearly document the involvement of mature supracrustal precursors (mafic volcanics ± clastic/chemical sediments) during the reworking of 3.86 Ga crust at ca. 3.5 Ga. This study provides unequivocal evidence for hydrosphere–crust interactions and reworking processes resulting in metamorphic zircon growth at ca. 3.5 Ga, namely 1 Ga before the Archean-Proterozoic transition. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.