Specific changes in its amino acid structure (racemization or epimerization) which occur at a slow, relatively uniform rate, are measured after the organism's death.The basis for the technique is the fact that almost all amino acids change from optically active to optically passive compounds (racemize) over a period of time.Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods.
When exposed to water that contains fluoride, a fluoride ion (F-) can replace a hydroxyl ion (OH-) in the bone mineral.
Over time, buried bones pick up fluoride ions from soil moisture or exposure to groundwater.
Older specimens have higher fluoride contents than younger ones when burial conditions are identical.
The methods used by archaeologists to gather data can be applied to any time period, including the very recent past. This “garbology” project proved that even recent artifacts can reveal a lot about the people who used and discarded them.
has become known for his study of the garbage discarded by the people of Tuscon, Arizona in the 1970s!