Varve analysis dating method
As the microclimate changes, through weather conditions or human intervention, the balance of vegetation changes, and so the frequency of pollen types.These changes yield up a sequence that can be used in that period and locality to date other finds.
Seriation uses the distribution law to distinguish strata from the frequency that an artifact occurs.
Objects are slowly introduced into a culture, gradually increase in popularity and then declines in use and disappear.
It is necessary that: The half-life of carbon-14 is 5730 ± 40 years.
Modern C-14 has a beta radiation count of about 15 (electrons) per minute per gram of carbon, but C-14 that is 5730 years old has a count of only 15 electrons every two minutes. Beyond 60,000 years, there is not enough carbon-14 left to measure this way.
Using an accelerator mass spectrometer (AMS) involves actually counting individual carbon-14 atoms, and therefore gives precise answers to the relative amounts of C-12 and C-14, which allows older and smaller samples to be dated, but it is expensive.