Geochemical Prospecting of a Uraniferous Bog Deposit at Masugnsbyn, Northern Sweden

In connection with prospecting for uranium ores in northern Sweden a peat bog, situated 4.5 km NW of Masugnsbyn, Norrbotten, Sweden and showing a remarkable content of uranium, was discovered. Closer investigation of several samples of the peat indicated that the comparatively high content of uranium and radon was connected with the occurrence of radioactive springs in the region. It was found that four different kinds of water were responsible for the supply of radioactive material to the peat, viz: ground water, surface water, spring water and ground water emanating from fractured rock. The spring water - probably a mixture of ground water and water from the fractured rock - contains uranium to the extent of micrograms per litre. The pH is about 7. The uranium content of the water system deriving from the fractured rock is about 200-300 micrograms per litre. The maximum radon content is about 3000 emans. The pH is >7 and the specific conductivity about 150 x 10-6/Ohm/cm The radioactive peat is characterised by extremely low gamma radioactivity which may be due to the recent emplacement of uranium by spring waters. It is suggested that the peat in question has served as a 'collector' for uranium, rare earth metals etc., since the pH condition - pH about 7 - was favourable to the settling of these elements. The uranium enrichment seems to be due to a transport of Na, Mg and Ca bicarbonates emanating from dolomite deposits or pegmatitic granite dikes in the vicinity of the peat, the bicarbonate waters serving as carriers of the uranium