Geology and mineralogy of the Sarfartôq carbonatite complex, southern West Greenland

Karsten Secher, Lotte Melchior Larsen

    Publikation: Bidrag til tidsskriftArtikelForskningpeer review

    66 Citationer (Scopus)

    Resumé

    The Sarfartôq carbonatite complex was emplaced in lower Palaeozoic time in a weakness zone within the Precambrian shield. Dolomitic magma intruded in two major stages of activity. In the first stage a steeply dipping conical body of concentric sheets of rauhaugite was formed, while in the second stage several batches of magma were emplaced into the surrounding marginal shock-zone as concentric and radial beforsite dykes and agglomerates. Hydrothermal activity gave rise to several phases of mineralisation in veins and shear zones. The accompanying fenitisation was of the Na-type. The whole complex covers about 90 km2. The main rock-forming minerals are dolomite-ankerite, apatite, orange reversely pleochroic phlogopite, richterite-arfvedsonite and magnetite. Important accessories are pyrochlore, zircon and niobian rutile. A complete mineral list is given, together with microprobe data on mineral chemistry. The dolomitic magmas were poor in SiO2, Al2O3 and K2O in relation to other carbonatites. Nb, U and LREEs are strongly enriched in pyrochloremineralised zones where the Nb content may be up to 40%. Some shear zones are strongly enriched in Th and HREEs (specifically Eu) and lesser Pb and Zn. Niobium, uranium, rare earth elements and phosphorus occur in economically interesting concentrations.

    OriginalsprogEngelsk
    Sider (fra-til)199-212
    Antal sider14
    TidsskriftLithos
    Vol/bind13
    Udgave nummer2
    DOI
    StatusUdgivet - 15 apr. 1980

    Programområde

    • Programområde 4: Mineralske råstoffer

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