preliminary description of one of the voluminous oversaturated syenites of the East Greenland Tertiary

• Main Author: C. Kent Brooks
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland; East Greenland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.606.7735; http://2dgf.dk/xpdf/bull38-03-04-145-151.pdf

The Kræmer 0 syenite, situated close to the Skaergaard intrusion, is typical of many oversturated syenites in the area. It consists of a maginal breccia with a sharp contact to the surrounding gneisses. This breccia, about 150 m wide is made up of basaltic clasts in a granitic matrix. It is associated with pegmatites, aplites and granophyres, all with a non-peralkaline characters. The main part of the syenite is a coarse-grained, massively jointed body with many large basic xenoliths and occasional modal layering. It is associated with peralkaline rhyolitic dikes and pegmatites. Anatexis of basement and crystal differentiation from a basaltic magma are thought to be unlikely processes to explain the origin of the syenites although the breccia matrix appears to be a simple partial melt of the gneisses. It is postulated that such an anatectic melt, formed by heat transfer from basaltic magmas, becomes modified by diffusive interchange with the basaltic melt to generate the syenite in the way described for a nearby locality by Nielsen & Brooks (1988).