Record details

Title
    Timing of ophiolite obduction in the Grampian orogen
Author
    Chew, D.
    Daly, J.S.
    Kirkland, C.
    Lam, R.
    Magna, Tomáš
    Page, L.
    Whitehouse, M.
Language
    anglicky
Publication type
    článek v periodiku
Source title - serial
    Geological Society of America Bulletin
Vol./nr.
    Roč. 122, č. 11/12
Pages
    13
Year
    2010
Thesaurus term
    geochronology,Grampian orogen,ophiolite,Barrovian metamorphosis
Keyword
    Grampian
    Obduction
    Ophiolite
    Orogen
    Timing
Abstract (in english)
   We address the p-T-t conditions of ophiolite obduction of the 470 Ma Grampian orogeny of Scotland and Ireland. This event gave rise to the main structural and metamorphic characteristics of the Grampian type area for Barrovian metamorphism. Zircons from the Highland Border ophiolite define a 499Ma U-Pb concordia age, interpreted as dating magmatism. Its metamorphism is dated by a 490Ma 40Ar-39Ar hornblende age, and a 488Ma 40Ar-39Ar muscovite age from a metasedimentary xenolith. Metamorphism of the Deerpark complex ophiolitic mélange is constrained by a 514Ma 40Ar-39Ar hornblende age, while mica schist slivers yield detrital zircon U-Pb ages consistent with Laurentian provenance and Rb-Sr and 40Ar-39Ar muscovite ages of ca. 482 Ma. Metamorphic mineral ages from the Grampian terrane (Dalradian Supergroup) are substantially younger (ca. 475-465Ma). If conductive heating in overthickened crust caused Barrovian metamorphism, then collisional thickening must have started soon after ophiolit
   e obduction.
Contributor
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
    R
Import date
    15. 10. 2014