U-Pb and Lu-Hf isotope systematics of zircons from the Mississippi River sand: Implications for reworking and growth of continental crust

Abstract

Research Article| June 01, 2005 U-Pb and Lu-Hf isotope systematics of zircons from the Mississippi River sand: Implications for reworking and growth of continental crust Tsuyoshi Iizuka; Tsuyoshi Iizuka 1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama Meguro-ku, Tokyo 152-8551, Japan Search for other works by this author on: GSW Google Scholar Takafumi Hirata; Takafumi Hirata 1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama Meguro-ku, Tokyo 152-8551, Japan Search for other works by this author on: GSW Google Scholar Tsuyoshi Komiya; Tsuyoshi Komiya 1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama Meguro-ku, Tokyo 152-8551, Japan Search for other works by this author on: GSW Google Scholar Shuji Rino; Shuji Rino 1Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama Meguro-ku, Tokyo 152-8551, Japan Search for other works by this author on: GSW Google Scholar Ikuo Katayama; Ikuo Katayama 2Department of Geology and Geophysics, Yale University, New Haven, Connecticut 06520, USA Search for other works by this author on: GSW Google Scholar Akihisa Motoki; Akihisa Motoki 3Department of Igneous Petrology, Rio de Janeiro State University, Rua Sao Francisco Xavier 524, Sala A-4023, Maracana, Rio de Janeiro, Brazil Search for other works by this author on: GSW Google Scholar Shigenori Maruyama Shigenori Maruyama 4Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Ookayama Meguro-ku, Tokyo 152-8551, Japan Search for other works by this author on: GSW Google Scholar Geology (2005) 33 (6): 485–488. https://doi.org/10.1130/G21427.1 Article history received: 29 Nov 2004 rev-recd: 07 Feb 2005 accepted: 09 Feb 2005 first online: 03 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 Tsuyoshi Iizuka, Takafumi Hirata, Tsuyoshi Komiya, Shuji Rino, Ikuo Katayama, Akihisa Motoki, Shigenori Maruyama; U-Pb and Lu-Hf isotope systematics of zircons from the Mississippi River sand: Implications for reworking and growth of continental crust. Geology 2005;; 33 (6): 485–488. doi: https://doi.org/10.1130/G21427.1 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 We carried out in situ U-Pb and Lu-Hf isotope analyses of detrital zircons from the Mississippi River in order to understand crustal reworking and continental growth rates. The U-Pb analyses for 416 zircons reveal three major peaks of crust formation at 2.8–2.6 Ga, 1.8–0.9 Ga, and after 0.2 Ga. Initial Hf isotope ratios were obtained for 402 of the dated zircons, and only 8% of the zircons have \(\ _{Hf(\mathit{T})_{DM}}\) values less negative than −2.5. These data correspond to a crustal residence time of <120 m.y. This finding indicates that crustal reworking was a very important process in continental crust formation. The \(\ _{Hf(\mathit{T})_{DM}}\) population demonstrates that reworking was predominant at 2.5–2.0 Ga and after 0.9 Ga, whereas juvenile crust formation dominated between 2.0 and 1.6 Ga. We calculated the mantle-extraction model ages to estimate the continental growth rate. Approximately half of the grains have model ages between 2.0 and 1.3 Ga, indicating rapid crustal growth during this time. The continental growth rate suggests that 15% and 78% crust in the source region of the zircons formed by 2.5 and 1.3 Ga, respectively. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.