Geochemical and petrological evidence for a suprasubduction zone origin of Neoarchean (ca. 2.5 Ga) peridotites, central orogenic belt, North China craton

Abstract

Research Article| July 01, 2006 Geochemical and petrological evidence for a suprasubduction zone origin of Neoarchean (ca. 2.5 Ga) peridotites, central orogenic belt, North China craton Ali Polat; Ali Polat 1Department of Earth Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada Search for other works by this author on: GSW Google Scholar Claude Herzberg; Claude Herzberg 2Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, USA Search for other works by this author on: GSW Google Scholar Carsten Münker; Carsten Münker 3Institut für Mineralogie, Universität Münster, Corrensstrasse 24, 48149 Münster, Germany, and Mineralogisch-Petrologisches Institut, Universität Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany Search for other works by this author on: GSW Google Scholar Rebecca Rodgers; Rebecca Rodgers 4Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, USA Search for other works by this author on: GSW Google Scholar Tim Kusky; Tim Kusky 5Department of Earth and Atmospheric Sciences, Saint Louis University, St. Louis, Missouri 63103, USA Search for other works by this author on: GSW Google Scholar Jianghai Li; Jianghai Li 6Department of Geology, Peking University, Beijing 100871, China Search for other works by this author on: GSW Google Scholar Brian Fryer; Brian Fryer 7Department of Earth Sciences, University of Windsor, Windsor, Ontario N9B 3P4, Canada, and Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario N9B 3P4, Canada Search for other works by this author on: GSW Google Scholar Jeremy Delaney Jeremy Delaney 8Department of Geological Sciences, Rutgers University, New Brunswick, New Jersey 08903, USA Search for other works by this author on: GSW Google Scholar GSA Bulletin (2006) 118 (7-8): 771–784. https://doi.org/10.1130/B25845.1 Article history received: 17 May 2005 rev-recd: 14 Nov 2005 accepted: 28 Feb 2006 first online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Ali Polat, Claude Herzberg, Carsten Münker, Rebecca Rodgers, Tim Kusky, Jianghai Li, Brian Fryer, Jeremy Delaney; Geochemical and petrological evidence for a suprasubduction zone origin of Neoarchean (ca. 2.5 Ga) peridotites, central orogenic belt, North China craton. GSA Bulletin 2006;; 118 (7-8): 771–784. doi: https://doi.org/10.1130/B25845.1 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 SocietyGSA Bulletin Search Advanced Search Abstract The 2.55–2.50 Ga Zunhua and Wutaishan belts within the central orogenic belt of the North China craton contain variably metamorphosed and deformed tectonic blocks of peridotites and amphibolites that occur in a sheared metasedimentary matrix. In the Zunhua belt, dunites comprise podiform chromitites with high and uniform Cr-numbers (88). Peridotites and associated picritic amphibolites are characterized by light rare earth element (LREE)–enriched patterns and negative high field strength element (HFSE: Nb, Zr, and Ti) anomalies. They have positive initial ϵHf values (+7.9 to +10.4), which are consistent with an extremely depleted mantle composition. Mass-balance calculations indicate that the composition of the 2.55 Ga mantle beneath the Zunhua belt was enriched in SiO2 and FeOT compared to modern abyssal peridotites. These geochemical signatures are consistent with a suprasubduction zone geodynamic setting. Metasomatism of the subarc mantle by slab-derived hydrous melts and/or fluids at ca. 2.55 Ga is likely to have been the cause of the subduction zone geochemical signatures in peridotites of the Zunhua belt.In the Wutaishan belt, chromitite-hosting harzburgites and dunites display U-shaped rare earth element (REE) patterns and have high Mg-numbers (91.1–94.5). These geochemical characteristics are similar to those of Phanerozoic forearc peridotites. The dunites might have formed by dissolution of orthopyroxene in reactive melt channels, similar to those in modern ophiolites. However, they differ in detail, and they might be residues of Archean komatiites. Following the initiation of an intra-oceanic subduction zone, they were trapped as a forearc mantle wedge between the subducting slab and magmatic arc. Slab-derived hydrous melts infiltrating through the mantle wedge metasomatized the depleted mantle residue, resulting in U-shaped rare earth element (REE) patterns. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.