2014/07/25 by D. R. Lowe, G. R. Byerly, Gary R. Byerly +2 · 6 citations
Earth and Planetary Sciences · Physics and Astronomy · #Geological and Geochemical Analysis #Planetary Science and Exploration #earthquake and tectonic studies
paper · doi:10.1130/g35743.1
openalex publication_date 2014/07/25 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Research Article| September 01, 2014 Recently discovered 3.42–3.23 Ga impact layers, Barberton Belt, South Africa: 3.8 Ga detrital zircons, Archean impact history, and tectonic implications Donald R. Lowe; Donald R. Lowe 1Department of Geological and Environmental Sciences, Stanford University, 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, Baton Rouge, Louisiana 70803, USA Search for other works by this author on: GSW Google Scholar Frank T. Kyte Frank T. Kyte 3Institute of Geophysics and Planetary Physics, University of California–Los Angeles, Los Angeles, California 90095, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Donald R. Lowe 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA Gary R. Byerly 2Department of Geology and Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803, USA Frank T. Kyte 3Institute of Geophysics and Planetary Physics, University of California–Los Angeles, Los Angeles, California 90095, USA Publisher: Geological Society of America Received: 02 Apr 2014 Revision Received: 08 Jun 2014 Accepted: 09 Jun 2014 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 © 2014 Geological Society of America Geology (2014) 42 (9): 747–750. https://doi.org/10.1130/G35743.1 Article history Received: 02 Apr 2014 Revision Received: 08 Jun 2014 Accepted: 09 Jun 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Donald R. Lowe, Gary R. Byerly, Frank T. Kyte; Recently discovered 3.42–3.23 Ga impact layers, Barberton Belt, South Africa: 3.8 Ga detrital zircons, Archean impact history, and tectonic implications. Geology 2014;; 42 (9): 747–750. doi: https://doi.org/10.1130/G35743.1 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 Barberton greenstone belt (BGB) includes eight known layers containing spherical particles (spherules) that condensed from rock vapor clouds formed by the impact of large meteorites or asteroids 3.47–3.23 Ga. Previous studies have inferred that the spherules represent bolides at least 20–70 km across. Spherule beds S1–S4 have been previously characterized in detail: we provide here the first detailed analysis of more recently discovered beds S5–S8. All eight beds are composed of the same basic compositional and textural spherule types, including nearly pure silica spherules representing nonaluminous melt precursors, nearly pure phyllosilicate spherules representing mostly mafic and ultramafic liquids, and compositionally mixed spherules. Evidence of spherule amalgamation and surface corrosion within the rock vapor clouds is developed in some beds. Bed S6, which occurs within a thick sequence of ultramafic volcanic rocks, is overlain by a tsunami layer containing zircons as old as 3811 ± 7 Ma, suggesting deep, possibly impact-related crustal uplift and erosion in distant areas. The formation of at least 8 major impact layers representing bolides 20–70 km in diameter over an interval of ∼240 m.y. suggests impact rates greatly exceeding those of later geologic time, and provides direct evidence that terrestrial bombardment by large bolides did not end abruptly at 3.8 Ga, but waned gradually until 3.0 Ga or even later. The coincidence of at least four large impact layers and the initiation of BGB deformation at 3.26–3.23 Ga suggests that an impact cluster at this time may have disrupted a long-lived earlier geodynamic system and triggered the development of a contrasting, more modern plate tectonic regime. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.