Pre-Quaternary geology of Southwest Greenland and its bearing on North Atlantic correlation problems

J.H. Allaart, D. Bridgwater, N. Henriksen

    Publikation: Bidrag til bog/rapport/konferenceproceedingsKonferenceartikel i proceedingspeer review

    Abstrakt

    Two major divisions of Precambrian plutonic rocks are present in West Greenland south of 62°30′ N lat. The oldest (pre-Ketilidian) rocks, giving ages between 2,500 and 2,700 m.y., are in the north. They consist mainly of gneisses, but include amphibolite and mica-schist and contain a belt of locally migmatized supracrustal rocks (the Tartoq Group). The gneisses and the supracrustal rocks are cut by several generations of cratogenic basic dikes.The pre-Ketilidian rocks are overlain unconformably by Ketilidian metasedimentary and metavolcanic rocks at approximately 61°15′ N lat. Southward the Ketilidian supracrustal rocks and the underlying gneisses and basic dikes are affected progressively by increasing deformation and plutonism in the Ketilidian mobile belt.In the Ketilidian mobile belt, which extends from approximately 61° 15′ N lat. to the southern tip of Greenland, two plutonic episodes are recognized: (1) the main Ketilidian plutonic episode (?1,800 m.y.), in which the main tectonic trends and metamorphic features of the mobile belt were established and large masses of granite were introduced, and (2) the Sanerutian plutonic episode, marked by renewed movement on older structures, reactivation of older granites, and emplacement of a suite of norite, diorite, and granite dated between 1,500 and 1,640 m.y.The subsequent cratogenic Gardar period was marked by major faulting, deposition of continental sand and associated volcanic rocks, and, during the period from 1,0 to 1,300 m.y. ago, by alkalic magmatism.The only post-Gardar–pre-Quaternary event recognized is the intrusion of a coast-parallel swarm of middle to late Phanerozoic basic dikes.Correlation possibilities between southwest Greenland and Labrador are suggested. Correlations between Greenland and Scotland of other than a general nature are regarded as less well founded.
    OriginalsprogUdefineret/Ukendt
    TitelNorth Atlantic—Geology and continental drift
    Undertitela symposium
    RedaktørerMarshall Kay
    ForlagAmerican Association of Petroleum Geologists
    Sider859-882
    Antal sider24
    ISBN (Trykt)9781629812274
    DOI
    StatusUdgivet - 1 jan. 1969
    BegivenhedInternational Conference on Stratigraphy and Structure Bearing on the Origin of the North Atlantic Ocean - Gander, Canada
    Varighed: 24 aug. 196730 aug. 1967

    Publikationsserier

    NavnMemoir American Association of Petroleum Geologists
    ForlagAmerican Association of Petroleum Geologists
    Vol/bind12

    Konference

    KonferenceInternational Conference on Stratigraphy and Structure Bearing on the Origin of the North Atlantic Ocean
    Land/OmrådeCanada
    ByGander
    Periode24/08/6730/08/67

    Programområde

    • Programområde 4: Mineralske råstoffer

    Citationsformater