Record details

    Timing of ophiolite obduction in the Grampian orogen
    Chew, D.
    Daly, J.S.
    Kirkland, C.
    Lam, R.
    Magna, Tomáš
    Page, L.
    Whitehouse, M.
Publication type
    článek v periodiku
Source title - serial
    Geological Society of America Bulletin
    Roč. 122, č. 11/12
Thesaurus term
    geochronology,Grampian orogen,ophiolite,Barrovian metamorphosis
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.
    Česká geologická služba
Contributor code
    ČGS (RIV)
Source format
Import date
    15. 10. 2014