title: Th-Rich Zircon from a Pegmatite Vein Hosted in the Wiborg Rapakivi Granite Massif
abstract: Zircon from a pegmatite vein hosted in the rapakivi granites occurring in the Gubanov Intrusion of the Wiborg Massif was shown by the EPMA method to contain an anomalously high Th of 18.3 wt% ThO2 (about 161,000 ppm Th). The SIMS method obtained a close value for thorium content—146,000 ppm. U increases to 6800 ppm. Zircon contains high values of other non-formula elements: Y (up to 51,500 ppm), Ti (up to 12,500 ppm), P (up to 9000 ppm), Nb (up to 3500 ppm), Ca (up to 2800 ppm) and Ba (up to 600
journal: Geosciences