Alkaline Rocks and Carbonatites of the World

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Goodwood River Plutons


Occurrence number: 
Longitude: -67.83, Latitude: 55.17

Three nepheline syenite intrusions lying some 65 km northwest of Schefferville, and close to the Goodwood River, are foliated and lineated parallel to the enclosing Superior Province gneisses, but also form dykes cutting them, so must have been intruded prior to the Kenoran Orogeny. All three plutons are similar in character, comprising essentially leucocratic nepheline syenite in which modal nepheline tends to increase towards the centre. Other minerals present include perthite, and locally microcline, poikilitic clinopyroxene, alkali amphibole, biotite and accessories. Nepheline syenite pegmatites occur as veins and concentrated adjacent to the country rocks, while a little ijolite is found as bands up to 10x2 m which may be dykes or xenoliths. Some layering is evident in the nepheline syenites, and xenoliths of metasomatized gneiss and granite are present.

K-Ar on biotite from nepheline syenite gave 2398±72 Ma.
Fumerton and Barry, 1984.
Fig. 1_76 The Goodwood River plutons (after Fumerton and Barry, 1984, Fig. 3).
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith