Petrography and geochemistty of amphibolites from the Nordre Strømfjord area in the central part of the Nagssugtoqidian of West Greenland

Abstract

The microstructures and general occurrence of orthopyroxene in the investigated amphibolites indicate that the rocks have been strongly deformed under granulite facies conditions. Microstructural features also suggest that high grade metamorphism in some cases outlasted deformation. The amphibolites show chemical resemblance to tholeiites from tectonic settings around active plate margins. Since chemical differentiation trends are not obvious, the results are insufficient to show that all the Nordre Strømfjord amphibolites originated in the same magmatic environment. The Nordre Strømfjord amphibolites may be Archaean or Proterozoic in age.