What is 137Cs?
In the late 1950s and mid 1960s there was an injection of radioisotopes into the atmosphere which occurred during nuclear testing. This injection can be used as a marker to identify soil and sediment particles laid down at that time.
Most of the fission products are in solid form and mix into the atmosphere and eventually settle to the earth’s surface as fallout. Study of fallout in the years immediately following atmospheric testing contributed immense amounts of knowledge to atmospheric mixing patterns. Today 137Cs is among the few fission products which are still detectable and this leads to its use as a tracer of sedimentation and erosion processes.