Beryllium mineralization in the Ilímaussaq intrusion, South Greenland

Abstract

In the peralkaline Ilimaussaq intrusion in South Greenland minor quantities of beryllium minerals are widespread in hydrothermal veins. Concentrations of veins rich in beryllium minerals are known from the Taseq slope and the Kvanefjeld area in the northern part of the intrusion. Up to now 10 beryllium minerals have been found, the most important being chkalovite. The hydrothermal veins range in width from about 1 mm to 2 m but are mostly a few cm thick. The most important minerals in the veins are analcime, sodalite, ussingite, natrolite, aegirine, arfvedsonite, epistolite and chkalovite. A field beryllometer based on the photoneutron method of determining beryllium is described. With a 100 mCi Sb¹²⁴ activation source the instrument has a limit of detection ofless than 10 ppm BeO. The effective measuring area is ca. 40 cm². Beryllium has a log-normal distribution in the rocks of the area.