Some Effects of Progressive Metamorphism on Zircons

Research Article| July 01, 1967 Some Effects of Progressive Metamorphism on Zircons R GORDON GASTIL; R GORDON GASTIL Dept. Geology, San Diego State College, San Diego, California Search for other works by this author on: GSW Google Scholar MARK DeLISLE; MARK DeLISLE Texaco Geophysical, Bakersfield, California Search for other works by this author on: GSW Google Scholar JR MORGAN JR MORGAN Dept. Geology, University of New Mexico, Albuquerque, New Mexico Search for other works by this author on: GSW Google Scholar GSA Bulletin (1967) 78 (7): 879–906. https://doi.org/10.1130/0016-7606(1967)78[879:SEOPMO]2.0.CO;2 Article history received: 20 Jun 1966 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation R GORDON GASTIL, MARK DeLISLE, JR MORGAN; Some Effects of Progressive Metamorphism on Zircons. GSA Bulletin 1967;; 78 (7): 879–906. doi: https://doi.org/10.1130/0016-7606(1967)78[879:SEOPMO]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract To investigate the metamorphism of zircons, the authors studied the aureole of a moderate-sized Mesozoic pluton, a large Mesozoic batholith, and progressive zones of Paleozoic regional metamorphism. The study confirmed the following: (1) metadetrital zircons refacet only at near-melting conditions and even then are distinguishable from typical igneous crystals; (2) uranium-plus-thorium content decreases with increased grain size; (3) lead loss is closely related to uranium-thorium content; and (4) independent of uranium-thorium content, zircons show increased lead loss with increased grade of metamorphism, the degree of loss appearing to increase with the duration of heating. It further confirmed that granitic rocks may incorporate metadetrital zircons containing older radiogenic lead and that the zircon “radioactivity clock” is rarely if ever entirely reset by metamorphism.The study showed that hyacinth zircons lose their color progressively with increasing metamorphism and that the color loss is a function of maximum temperature rather than thermal duration. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.