Research Article| August 01, 2003 Geochronology of the Mesoproterozoic State Farm gneiss and associated Neoproterozoic granitoids, Goochland terrane, Virginia Brent E. Owens; Brent E. Owens 1Department of Geology, College of William and Mary, Williamsburg, Virginia 23187, USA Search for other works by this author on: GSW Google Scholar Robert D. Tucker Robert D. Tucker 1Department of Geology, College of William and Mary, Williamsburg, Virginia 23187, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Brent E. Owens 1Department of Geology, College of William and Mary, Williamsburg, Virginia 23187, USA Robert D. Tucker 1Department of Geology, College of William and Mary, Williamsburg, Virginia 23187, USA Publisher: Geological Society of America Received: 14 Sep 2002 Revision Received: 15 Jan 2003 Accepted: 07 Feb 2003 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2003) 115 (8): 972–982. https://doi.org/10.1130/B25258.1 Article history Received: 14 Sep 2002 Revision Received: 15 Jan 2003 Accepted: 07 Feb 2003 First Online: 02 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 Brent E. Owens, Robert D. Tucker; Geochronology of the Mesoproterozoic State Farm gneiss and associated Neoproterozoic granitoids, Goochland terrane, Virginia. GSA Bulletin 2003;; 115 (8): 972–982. doi: https://doi.org/10.1130/B25258.1 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 Goochland terrane is an isolated block of Mesoproterozoic crust in the Piedmont Province of central Virginia. We report U-Pb zircon dates and whole-rock major and trace element data for the State Farm gneiss, one of the main units in the terrane, and additional results for a newly recognized suite of Neoproterozoic granitoids that intrude the gneiss. The State Farm gneiss ranges in bulk composition from quartz monzodiorite to granite, and three samples yield U-Pb zircon dates of 1046 +7/–6 Ma, 1039 +18/–11 Ma, and 1023 ± 10 Ma. We interpret these dates as igneous crystallization ages, which indicate a maximum emplacement interval of ca. 1057–1013 Ma for these samples. Neoproterozoic granitoids (including the Fine Creek Mills and Flat Rock granites) are more alkaline than the State Farm gneiss and display all compositional characteristics of A-type granites (e.g., high Fe/Mg, Ga, Ga/Al, Nb, Zn, Y, Zr). U-Pb zircon analyses from five separate bodies indicate crystallization ages from ca. 654 to 588 Ma, but all results are complicated by Mesoproterozoic (ca. 1 Ga) inheritance, coupled, in some cases, with secondary Pb loss. We interpret the ages and compositions of the younger rocks to reflect Neoproterozoic rifting of the Goochland terrane, but its location during rifting is uncertain. The terrane may have been separated from Laurentia during the Neoproterozoic breakup of Rodinia and later reattached. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.