An occurrence of ironstone enclaves east of Sukkertoppen, southern West Greenland

Abstract

Helicopter reconnaissance mapping began in 1976 in the Godthåbsfjord region (Allaart et al., 1977) progressed northwards as far as Evighedsfjord, north of Sukkertoppen during the summer of 1977 (Allaart et al., this report). Amitsoq and Nfik type gneisses were widely recognised in the inner Godthåbsfjord region and the stratigraphy determined from coastal work by McGregor (1973) was corroborated. Friend & Hall (1977) have described the discordant relationship of Nfik gneiss sheets to the older Amitsoq banded gneisses in the Ivisartoq area. North of the Ataneq fauit, which runs from Isua south-west into Godthåbsfjord, amphibolite horizons occur as complex interference fold structures within the predominant homogeneous, poorly foliated granitic (sensu lato) bodies such as the Taserssuaq granodiorite (Allaart et al., 1977) which are believed by the field geologists to be of Nfik age. These rocks grade into gneisses and pegmatites rich in amphibolite agmatite and/or enclaves which continue to Evighedsfjord in amphibolite to granulite facies.