Sedimentation Rates in Lake Pukaki, New Zealand

摘要

The layers of Lake Pukaki sediments and their possible relationship to other cyclic events have been considered with a view to determining the rate of sediment deposition. There was no evidence to determine whether the rhythmic layers in the sediments are annual deposits or controlled by flood conditions. In the hope of resolving the question, radiometric dating techniques were applied to sediment cores in which the concentrations of radionuclides such as lead 210 and caesium 137 were measured with respect to depth and then related to some known input pattern. exp 210 Pb and exp 137 Cs were determined in all three cores investigated. exp 147 Pr and exp 144 Ce were also determined in one of the cores. The exp 137 Cs measurements indicated sedimentation rates of 14 kg/y/m exp 2 for one core and 17 kg/y/m exp 2 for the other two. (Atomindex citation 09:410870)