Reconnaissance geochemical mapping of the Paamiut region (61°25' to 62°45'N, 48°00' to 50°00'W), South-West Greenland

Geochemical mapping by means of analysis of stream sediment and water collected at a density of 1 sample per 20-30 km² has been carried out over the southern part of the Archaean craton in West Greenland. The <0.1 mm fraction of the sediment samples was analysed by X-ray fluorescence and instrumental neutron activation techniques and results are reported for 41 major and trace elements. The conductivity and fluoride content of the water samples were determined.

The distribution of geochemical anomalies in the survey area indicates that base metal and gold mineralisation is associated with the Tartoq Group (basic metavolcanic and metasedimentary rocks) and also with large enclaves of metavolcanic supracrustal rocks in the gneisses on both sides of Kvanefjord, east of Paamiut. High values of Cr and Ni reflect the presence of ultramafic rocks in the amphibolitic enclaves.

A distinct geochemical province (high in lithophile elements and Y) is associated with a granitic complex in the south-eastern part of the region. Otherwise the gneiss terrain is low in LIL elements, high in N~O, CaO and Sr, and geochemically resembles that of the Fiskenæsset area to the north of Frederikshåb Isblink.

Anomalies of Au, Mo, Pb and Au appear to be associated with shear and fault zones and indicate hydrothermal mineralisation of possible Proterozoic age.