Pb 210 dating technique
A number of studies have focused on the accumulation of heavy metals during the past 100 years.
If the concentration of substances at different depths is compared with the corresponding ages, the accumulation rates of these substances at different times may be determined from the sediment accumulation rate.
The sediment samples must remain totally undisturbed during sampling to obtain the best possible dating.
Subsequently, they are cut into slices of approximately 1 cm and dried, whereupon the content of dry matter and possibly the loss on ignition are determined.
The sediment dating may be supplemented with estimations of the content of alga pigments in the depths required.
Thus, it will be possible not only to describe the sediment age, but also to give a picture of the dominant mixture of plankton alga at the same time.
Pb activity (half-life = 22.3 years) to determine the rate of sediment accumulation.
About 5 g of dried sample, from various depths of the sediment core, is required.
The samples are simply packed into petri dishes or vials, left to equilibrate for three weeks and then counted on a High Purity Germanium (HP-Ge) gamma spectrometry system.However the method is destructive and other radionuclides such as Pb dating can be undertaken by gamma spectrometry technique.