Natural vs. synthetic graphite, page-88

Thorium and Uranium in the Nunasvaara key area
Geophysical work at Nunasvaara included gamma spectrometer measurements and the collection of petrophysical samples. Airborne uranium data for the area generally shows low uranium concentrations (c. 0.3–4 ppm) across the greenstone pile. Spectrometer measurements on Lower greenstone group basalts in the centre of the key area returned average concentrations of 0.5% potassium, 0.4 ppm uranium and 0.4 ppm thorium (n=4). Basaltic tuffs (Upper greenstone formation) further to the west returned average concentrations of 0.1% potassium, 0.0 ppm uranium and 0.3 ppm thorium (n=2), while measurement of a scapolitised dioritic intrusion, close to the amphibole breccia previously described, gave average concentrations of 0.2% potassium, 0.7 ppm uranium and 7.0 ppm thorium (n=3). Higher uranium concentrations (c. 3–10 ppm) occur to the south of the key area, coincident with several granitic intrusions and known uranium mineralisation. Spectrometer measurements on coincident with an airborne-derived high uranium anomaly, granite and rhyolite is well exposed. Here, granitic bedrock returned average concentrations of 3.9 % potassium, 27 ppm uranium and 21 ppm thorium, while concentrations in the rhyolite were 6.0% potassium, 12 ppm uranium and 11 ppm thorium. Locally, the granite in this area has uranium concentrations up to 84 ppm which confirms the anomalous nature of the area granite outcrops close to route E45 gave average concentrations of 4.0% potassium, 3 ppm uranium and 22 ppm thorium (n=9). Further to the west, coincident with an airborne-derived high uranium anomaly, granite and rhyolite is well exposed. Here, granitic bedrock returned average concentrations of 3.9 % potassium, 27 ppm uranium and 21 ppm thorium, while concentrations in the rhyolite were 6.0% potassium, 12 ppm uranium and 11 ppm thorium. Locally, the granite in this area has uranium concentrations up to 84 ppm which confirms the anomalous nature of the area.

http://resource.sgu.se/produkter/sgurapp/s1404-rapport.pdf

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