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Carboniferous U-Pb age of the Sebago batholith, southwestern Maine: Metamorphic and tectonic implications
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1985
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Earth ScienceEngineeringStructural GeologyPrecambrian GeologyGeographySedimentary GeologySebago BatholithEconomic GeologyGeologyEarth SciencesSouthwestern MaineGeological DataGeochronologyPetrologyRegional GeologyIntegrated StratigraphyCarboniferous U-pb AgeTectonics
Research Article| August 01, 1985 Carboniferous U-Pb age of the Sebago batholith, southwestern Maine: Metamorphic and tectonic implications JOHN N. ALEINIKOFF; JOHN N. ALEINIKOFF 1U.S. Geological Survey, Box 25046, Federal Center, M.S. 963, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar ROBERT H. MOENCH; ROBERT H. MOENCH 1U.S. Geological Survey, Box 25046, Federal Center, M.S. 963, Denver, Colorado 80225 Search for other works by this author on: GSW Google Scholar JOHN B. LYONS JOHN B. LYONS 2Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755 Search for other works by this author on: GSW Google Scholar Author and Article Information JOHN N. ALEINIKOFF 1U.S. Geological Survey, Box 25046, Federal Center, M.S. 963, Denver, Colorado 80225 ROBERT H. MOENCH 1U.S. Geological Survey, Box 25046, Federal Center, M.S. 963, Denver, Colorado 80225 JOHN B. LYONS 2Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1985) 96 (8): 990–996. https://doi.org/10.1130/0016-7606(1985)96<990:CUAOTS>2.0.CO;2 Article history First Online: 01 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 JOHN N. ALEINIKOFF, ROBERT H. MOENCH, JOHN B. LYONS; Carboniferous U-Pb age of the Sebago batholith, southwestern Maine: Metamorphic and tectonic implications. GSA Bulletin 1985;; 96 (8): 990–996. doi: https://doi.org/10.1130/0016-7606(1985)96<990:CUAOTS>2.0.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 SocietyGSA Bulletin Search Advanced Search Abstract Two phases (pink and white granite) of the Sebago batholith of southwestern Maine have been dated by the U-Pb zircon method. Identical upper concordia intercepts of both rocks indicate an intrusive age of 325 ± 3 m.y. for the batholith. The lower intercept of the pink-phase sample, 114 ± 13 m.y., is inferred to represent episodic lead loss due to the intrusion of the nearby Cretaceous Pleasant Mountain stock. The lower intercept of the white-phase sample, 18 ± 21 m.y., suggests only modern dilatancy lead loss. Monazites have ages of 272 m.y. (pink) and 282 m.y. (white) which are thought to be cooling ages. Rb-Sr whole-rock data have low initial 87Sr/86Sr ratios of 0.7031 (pink) and 0.7053 (white). These data, in conjunction with published 40Ar/39Ar, Rb-Sr, K-Ar, and fission-track ages, suggest that little or no uplift occurred in this part of New England until the Permian and that the uplift rate from 275 m.y. to 225 m.y. was ∼3 times as rapid as was the rate for 225 m.y. to the present. The Carboniferous age of the Sebago batholith suggests that currently accepted metamorphic and tectonic interpretations for southwestern Maine and for east-central New Hampshire require revision. 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.