Research Article| August 01, 1990 U/Pb zircon and baddeleyite ages for the Palisades and Gettysburg sills of the northeastern United States: Implications for the age of the Triassic/Jurassic boundary G. R. Dunning; G. R. Dunning 1Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada Search for other works by this author on: GSW Google Scholar J. P. Hodych J. P. Hodych 1Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada Search for other works by this author on: GSW Google Scholar Geology (1990) 18 (8): 795–798. https://doi.org/10.1130/0091-7613(1990)018<0795:UPZABA>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation G. R. Dunning, J. P. Hodych; U/Pb zircon and baddeleyite ages for the Palisades and Gettysburg sills of the northeastern United States: Implications for the age of the Triassic/Jurassic boundary. Geology 1990;; 18 (8): 795–798. doi: https://doi.org/10.1130/0091-7613(1990)018<0795:UPZABA>2.3.CO;2 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 Zircons extracted from the Palisades and Gettysburg sills and baddeleyite from the Palisades sill yield consistent U-Pb ages of 201 ±1 Ma. These sills are likely related to the lowermost basalt flows of the Late Triassic-Early Jurassic Newark Supergroup rift basins of the eastern margin of North America (because of the geochemical similarity of their high-Ti quartz tholeiites and because drilling suggests that the Palisades sill directly fed some of the lowermost flows). Because the lowermost flows of the Newark Supergroup are paleonto-logically assigned to the lowermost Hettangian, the 201 ±1 Ma age of the sills should be slightly younger than the age of the Triassic/Jurassic boundary. Our data support the age of 204 ±4 Ma assigned the Triassic/Jurassic boundary and suggest that recent K-Ar dating for the Hettangian flows of the Newark Supergroup, which yielded an average age of 190 ±3 Ma, is about 5% low. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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Dunning et al. (1990) studied this question.