Rb-Sr age of the New Hampshire Plutonic Series

Abstract

Research Article| December 01, 1977 Rb-Sr age of the New Hampshire Plutonic Series JOHN B. LYONS; JOHN B. LYONS 1Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755 Search for other works by this author on: GSW Google Scholar DONALD E. LIVINGSTON DONALD E. LIVINGSTON 2Laboratory of Isotope Geochemistry, Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Search for other works by this author on: GSW Google Scholar Author and Article Information JOHN B. LYONS 1Department of Earth Sciences, Dartmouth College, Hanover, New Hampshire 03755 DONALD E. LIVINGSTON 2Laboratory of Isotope Geochemistry, Department of Geosciences, University of Arizona, Tucson, Arizona 85721 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1977) 88 (12): 1808–1812. https://doi.org/10.1130/0016-7606(1977)88<1808:RAOTNH>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 B. LYONS, DONALD E. LIVINGSTON; Rb-Sr age of the New Hampshire Plutonic Series. GSA Bulletin 1977;; 88 (12): 1808–1812. doi: https://doi.org/10.1130/0016-7606(1977)88<1808:RAOTNH>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 Rb-Sr whole-rock isochrons for four main representatives of the syntectonic to post-tectonic New Hampshire Plutonic Series yield the following ages: Kinsman Quartz Monzonite, 411 ± 19 m.y.; Bethlehem Gneiss, 405 ± 78 m.y.; Spaulding Quartz Diorite, 402 ± 5 m.y.; and Concord Granite, 359 ± 11 m.y. (or 330 ± 3 m.y.?). The Kinsman and Spaulding ages are consistent with a growing number of Rb-Sr ages determined for northern Appalachian granites, which are of Early Devonian or younger geologic age, and represent a major magmatic pulse of the Acadian orogeny. Comparison of Rb-Sr ages and geology implies that the beginning of the Devonian Period can be no later than approximately 415 m.y. and that the entire Devonian time scale needs revision.The Concord Granite is at least 40 m.y. (possibly 70 m.y.?), younger than other members of the New Hampshire Plutonic Series, and its time of emplacement is therefore probably Late Devonian(?) or Mississippian(?).Isochron plots imply that, although the members of the New Hampshire Plutonic Series have been derived by anatexis of lower crustal rocks, there is admixture of and contamination by mantle-derived magmatic material. 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.