Radiometric dating tests
Before more precise absolute dating tools were possible, researchers used a variety of comparative approaches called relative dating.
These methods — some of which are still used today — provide only an approximate spot within a previously established sequence: Think of it as ordering rather than dating.
Measuring carbon-14 in bones or a piece of wood provides an accurate date, but only within a limited range.
Says Shea: “Beyond 40,000 years old, the sample is so small, and the contamination risk so great, that the margin of error is thousands of years.
This includes factoring in many variables, such as the amount of radiation the object was exposed to each year.
These techniques are accurate only for material ranging from a few thousand to 500,000 years old — some researchers argue the accuracy diminishes significantly after 100,000 years.
Generally speaking, the more complex a poem or piece of pottery is, the more advanced it is and the later it falls in the chronology.Unlike observation-based relative dating, most absolute methods require some of the find to be destroyed by heat or other means.This family of dating methods, some more than a century old, takes advantage of the environment’s natural radioactivity.Thermoluminescence: Silicate rocks, like quartz, are particularly good at trapping electrons.Researchers who work with prehistoric tools made from flint — a hardened form of quartz — often use thermoluminescence (TL) to tell them not the age of the rock, but of the tool.