REE CONTENTS IN FIFTY-TWO KARA SEA TROUGHS' SEDIMENT CORES, EUROPEAN ARCTIC

The rare earth elements (REE) La, Ce, Nd, Sm, Eu, Tb, Yb and Lu, plus Sc, were analysed in 476 samples from 52 cores taken in the East Novaya Zemlya, Voronin and St. Anna troughs, Kara Sea. The sediment is dominated by 60% clay-size and 30% silt-size fractions. There is little variation geographically or downcore in REE contents to >120 cm. At the estimated 0.1-0.6 mm/yr sedimentation rates for the troughs, the longest cores represent timeframes of between 2000 and 12000 yrs during which REE input has been rather constant. REE contents in the troughs' sediments are closer to those for the average shale than those for the average pelagic clay. The troughs contain 34 ppm La, 74 ppm Ce, 28 ppm Nd, 5.9 ppm Sm, 1.3 ppm Eu, 0.9* ppm Tb, 2.6 ppm Yb, 0.4 ppm Lu and 16 ppm Sc. Comparative values for the averge shale are 38, 80, 34, 5.6, 1.1, 0.8, 2.8, 0.4 and 16 ppm, respectively. For the average pelagic clay the comparative values are 42, 80, 41, 8.0, 1.8, 1.3, 3.8, 0.6 and 19 ppm, respectively. *145 samples had Tb at or above the 0.5 ppm detection limit.