Pb 210 dating
Least squares regression is used to determine the slope of the decay curve, from which the sedimentation rate can be calculated.The naturally lead isotope 210Pb may be used to date aquatic sediments and peat bogs.Results indicate that our cores contain sediments from the 20th Century and that sedimentation rates increased when the Bear River was diverted into the lake.The Pb-210 method is used to determine the accumulation rate of sediments in lakes, oceans and other water bodies.Various laboratory techniques have been utilized worldwide for measuring lead-210 in sub-recent deposits through its grand-daughter product polonium-210.Isotope dilution alpha spectrometry proved a suitable tool for absolute determination of lead-210 for the dating of aquatic deposits.Although the concentration of uranium varies from location to location, it is present in essentially all soils and sediments, at least at some low level.
Pb against depth or cumulative weight (to allow for compacting) will be a straight line if the sedimentation rate has been constant.
metal), if it is produced in soils close to the air-soil interface.
This radon emanation is a normal occurrence and thereby causes the terrestrial atmosphere to contain a low (~ 1 DPM/L = 1 disintegration per minute per litre) but fairly constant level of radioactive gas.
Uranium-238 is the first in the series; it decays into thorium, which decays into protactinium, which decays into uranium 234, and so on.
Note that the time it takes for each to decay varies from minutes to billions of years.