Field mapping of the pre-3760 m.y. old supracrustal rocks of the Isua area, southern West Greenland

Abstract

The first of a two-summer mapping programme on the Isua supracrustal rocks was undertaken as part of a larger mapping project aimed at the completion of the 1:500 000 map sheet søndre Strømfjord - Frederikshåb Isblink. The Isua supracrustal belt with its major occurrence of banded ironstone was discovered and mapped by geologists of Kryolitselskabet Øresund A/S (Keto, 1970). A Pb-Pb whole rock isochron age of 3760±70 m.y. for the banded ironstone has been obtained by Moorbath et al. (1973). Bridgwater & McGregor (1974) spent 14 days in the area in 1973.