Final answer:
Radiocarbon dating, using the radioactive isotope carbon-14, is the absolute dating method most often used at hominid sites to date organic materials between 300 and 50,000 years old. Other methods, such as thermoluminescence, are used for dating older materials or in the absence of organic matter.
Step-by-step explanation:
The absolute dating technique most often used on hominid sites is radiocarbon dating. Radiocarbon dating, which uses the radioactive isotope carbon-14 (carbon-14 or 14C), is a method applied to estimate the age of organic materials. The principle behind this technique involves measuring the remaining amount of radioactive carbon in the archaeological sample. As the radioactive isotope decays at a known rate, scientists can calculate the time that has passed since the organism's death, with an effective range for samples between 300 and 50,000 years old.
In contexts where organic material is not present or where the dates required exceed the limits of radiocarbon dating, other methods like thermoluminescence dating are employed. Thermoluminescence is especially useful when either the fossils themselves or the sediments around them have been heated by a high-temperature event, such as a volcanic eruption, resetting the 'dating clock' of the material. The subsequent analysis of trapped electrons released from mineral crystals upon heating provides an age estimate of when this heating event occurred.
Absolute dating methods are essential in paleoanthropology, providing more precise chronological frameworks than relative dating techniques like stratigraphy, which can only determine the sequence of events without providing numerical ages.