Detrital zircon geochronology of sandstones of the 3.6–3.2 Ga Barberton greenstone belt: No evidence for older continental crust

Research Article| July 26, 2017 Detrital zircon geochronology of sandstones of the 3.6–3.2 Ga Barberton greenstone belt: No evidence for older continental crust Nadja Drabon; Nadja Drabon 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar Donald R. Lowe; Donald R. Lowe 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar Gary R. Byerly; Gary R. Byerly 2Department of Geology and Geophysics, Louisiana State University, 354 Howe-Russell, Baton Rouge, Louisiana 70803, USA Search for other works by this author on: GSW Google Scholar Jacob A. Harrington Jacob A. Harrington 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Nadja Drabon 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Donald R. Lowe 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Gary R. Byerly 2Department of Geology and Geophysics, Louisiana State University, 354 Howe-Russell, Baton Rouge, Louisiana 70803, USA Jacob A. Harrington 1Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, California 94305, USA Publisher: Geological Society of America Received: 20 Apr 2017 Revision Received: 05 May 2017 Accepted: 08 May 2017 First Online: 26 Jul 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2017 Geological Society of America Geology (2017) 45 (9): 803–806. https://doi.org/10.1130/G39255.1 Article history Received: 20 Apr 2017 Revision Received: 05 May 2017 Accepted: 08 May 2017 First Online: 26 Jul 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Nadja Drabon, Donald R. Lowe, Gary R. Byerly, Jacob A. Harrington; Detrital zircon geochronology of sandstones of the 3.6–3.2 Ga Barberton greenstone belt: No evidence for older continental crust. Geology 2017;; 45 (9): 803–806. doi: https://doi.org/10.1130/G39255.1 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 crustal setting of early Archean greenstone belts and whether they formed on or associated with blocks of older continental crust or in more oceanic settings remains a major issue in Archean geology. Here we report detrital zircon U-Pb age data from sandstones of the 3.26–3.20 Ga Fig Tree and Moodies Groups and from 3.47 to 3.23 Ga meteorite impact–related deposits in the 3.55–3.20 Ga Barberton greenstone belt (BGB), South Africa. The provenance signatures of these sediments are characterized by zircon age peaks at 3.54, 3.46, 3.40, 3.30, and 3.25 Ga. These clusters are coincident either with the ages of major episodes of felsic to intermediate igneous activity within and around the belt or with the ages of thin felsic tuffs reflecting distant volcanic activity. Only 15 of the reported 3410 grains (<0.5%) pre-date the age of the oldest rocks in the BGB. The extreme rarity of zircons older than the felsic components of the BGB itself, even after widespread deformation, uplift, and deep erosion of the BGB, implies that an older continental substrate is unlikely to have existed beneath or adjacent to the BGB. Ten of the 15 pre-BGB zircons were recovered from a single meteorite impact–related layer and may have been derived from far beyond the BGB by impact-related processes. The remaining old zircons could represent felsic rocks in older, unexposed parts of the BGB sequence, but are too few to provide evidence for a continental source. This finding offers further evidence that the large, thick, high-standing, highly evolved blocks of continental crust with an andesitic bulk composition that characterize the Earth during younger geologic times were scarce in the early Archean. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.