Analysis of uranium ore concentrates for origin assessment

In this study the most important analytical methodologies are presented for the nuclear forensic investigation of uranium ore concentrates (yellow cakes). These methodologies allow to measure characteristic parameters which may be source material or process inherited. By the combination of the various techniques (e.g. infrared spectrometry, impurity content, rare-earth pattern and U, Sr and Pb isotope ratio analysis by mass spectrometry), the possible provenances of the illicit material can be narrowed down to a few options and its declared origin can be verified. The methodologies serve for nuclear forensic investigations as well as for nuclear safeguards, checking the consistency of information.

The diagnostic geochemistry, relative abundance, and spatial distribution of high-calcium, low-alkali olivine tholeiite dykes in the Lower Tertiary regional swarm of the Isle of Skye, NW Scotland

SummaryDykes from four sections across the axis of the Skye regional swarm have been analysed for major elements, Nb, Rb, Sr, Y, Zr, and rare-earth elements. 70 % of the dykes are characterized by relatively high CaO (11–12%), and low abundance of elements such as TiO2 (∼1%), K2O (0·05–0·20 %), Zr (30–60 ppm), with a light-rare-earth depleted chondrite normalized pattern. The remainder of the swarm comprises dykes equivalent in composition to the Skye Main Lava Series and dykes belonging to a further magma type distinguished by a flat chondrite normalized rare-earth pattern. The high-calcium, low-alkali tholeiite dykes are confined to a narrow persistent zone forming the major axis of dilation of the swarm; other basaltic dykes are axially less persistent and have a wider lateral distribution. The more evolved dykes tend to be restricted to central Skye.