Jr. Goff et al., PB-210 CHRONOLOGY FROM WELLINGTON HARBOR, NEW-ZEALAND, New Zealand Journal of Marine and Freshwater Research, 32(2), 1998, pp. 181-186
A sediment accumulation record based on the levels of ''unsupported''
Pb-210 was obtained from a core taken from the centre of Wellington Ha
rbour, New Zealand. Sediment accumulation rates (SARs) varied from 3 t
o 5 mm yr(-1). Before 1920, SARs were sufficiently high to dilute unsu
pported levels of Pb-210 to background, but had fallen below the mean
by 1925 maintaining constant SARs until 1953. These data provide a hig
her resolution chronology of early 20th century SARs than was previous
ly available. Comparison with Cs-137 data confirms that there was a si
gnificant increase in SARs between 1953 and 1967, but that these have
remained fairly constant since 1974. Data from the two radionuclides a
re consistent after 1974, and Pb-210 data are consistent with other ch
ronological measurements before 1953. Therefore, it is suggested that
the two radionuclides are immobile in the marine sediments of Wellingt
on Harbour and that differences between the two SARs are real.