The Nordre Strømfjord shear zone and the Arfersiorfik quartz diorite in Arfersiorfik, the Nagssugtoqidian orogen, West Greenland

• Published in: Geological Survey of Denmark and Greenland (GEUS) Bulletin
• Main Authors: Sørensen, Kai, Korstgård, John A., Glassley, William E., Møller Stensgaard, Bo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Geological Survey of Denmark and Greenland (GEUS) 2006
• Subjects: aeromagnetic data; Arfersiorfik quartz diorite; deformation; geochemistry; Nagssugtoqidian; Nordre Strømfjord shear zone; West Greenland; Greenland; Nordre Strømfjord; Arfersiorfik; Nordre strømfjord
• Online Access: https://geusbulletin.org/index.php/geusb/article/view/4922; https://doi.org/10.34194/geusb.v11.4922

The Nordre Strømfjord shear zone in the fjord Arfersiorfik, central West Greenland, consists of alternating panels of supracrustal rocks and orthogneisses which together form a vertical zone up to 7 km wide with sinistral transcurrent, ductile deformation, which occurred under middle amphibolite facies conditions. The pelitic and metavolcanic schists and paragneisses are all highly deformed, while the orthogneisses appear more variably deformed, with increasing deformation evident towards the supracrustal units. The c. 1.92 Ga Arfersiorfik quartz diorite is traceable for a distance of at least 35 km from the Inland Ice towards the west-south-west. Towards its northern contact with an intensely deformed schist unit it shows a similar pattern of increasing strain, which is accompanied by chemical and mineralogical changes. The metasomatic changes associated with the shear zone deformation are superimposed on a wide range of original chemical compositions, which reflect magmatic olivine and/or pyroxene as well as hornblende fractionation trends. The chemistry of the Arfersiorfik quartz diorite suite as a whole is comparable to that of Phanerozoic plutonic and volcanic rocks of calc-alkaline affinity.