Techniques Used for Absolute Dating in Archeology

In their research efforts to increase the validity of their findings, many archaeologists put to use absolute dating techniques to assign a chronological background to all materials they find. Absolute dating techniques, also known as chronometric dating techniques, are methods in which archeologists utilize chemistry and physics to determine the ages of a particular piece of material, artifact, or cultural remains. Some of absolute dating techniques are radiocarbon dating, dendrochronology, and potassium-argon dating.

Radiocarbon dating is one of the most widely used techniques. This method is used to determine the age of organic substances such as bone, charcoal, shell, or wood by measuring the amount of the carbon isotope, carbon-14, remaining in them. The technique focuses on carbon-14, an unsteady radioactive isotope of carbon, which decays away at a steady rate. Organisms seize a certain amount of carbon-14 from the atmosphere when they are alive. By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be calculated, thus giving an age for the material in question. Radiocarbon dating is usually used for determining ages up to about 50,000 years old, because dating older materials is much less accurate with this method. The relationship between the age estimates, also known as radiocarbon years and calendar years varies through time. Due to the distinctive variation in the richness of the radioactive isotope, carbon-14, archeologists must adjust the radiocarbon dates using sets of dates obtained from tree rings in the trunks of very long-lived tree species like the bristlecone pine to bring the radiocarbon years and calendar year to agreement.

Dendrochronology is a method of dating based on the number of rings of growth found in a tree trunk. For example, living trees create distinctive layers of growth rings[->0] each year of its life, which vary in thickness, dependent on the amount of rainfall available to the tree. Thus add thin rings during dry years and thick rings during wet years. By looking at the pattern of rings in a tree trunk, archeologists can date the materials in question and sometimes explain subtle cultural shifts spurred by the weather conditions that the tree witnessed. However, dendrochronology can only be applied in dating wooden objects.

Potassium-argon dating is another valuable method used by archeologists to date very old artifacts and sites. Like radiocarbon dating, potassium-argon dating depends on measuring radioactive emissions and the ratio of potassium to argon in minerals or rocks. This technique was employed and had yielded some accurate results in archaeological sites at Olduvai and East Africa, because the fossils and artifacts discovered there were found in between layers of volcanic ashes. Potassium-argon dating is very useful for archeologists to discover more about the time line of 50,000 to 200,000 years ago, which is a critical human evolutionary period.

Despite the fact that a great majority of results are in estimates and statistical terms, absolute dating techniques had brought about revolutionizing outcomes in archaeology. These illuminating findings enable the archeologists to reconstruct human technological developments, migrations, and origins, which give us the knowledge to better understand what makes us different from each other and what we have in common.