ANTH 210 Lecture Notes - Lecture 18: Optically Stimulated Luminescence, Laetoli, Mary Leakey
Document Summary
Other methods of dating occurs at constant and known rates: other radiometric techniques . Fission track rate of spontaneous uranium fission: potassium argon technique (k-ar) Measure amount of argon 40 in volcanic rock sample. Useful for rock formed prior to 100,000 bp. Example: laetoli footprints found in tanzania by mary leakey by australopithicus 3. 6 million years ago: optically stimulated luminescence (osl) Electrons are released under exposure to solar radiation (sunlight) Start obtaining electrons again when removed from sunlight. Shine light onto soil or stone artifact, measure how light bounces off of it, determines how long its bene in the dark. Example of indirect dating: direct dating. Uses artifact ecofact or feature itself to determine age. Radiocarbon dating is example: indirect dating. Dates an artifact, ecofact or feature by its association with other material/ matrix/ strata that can be dated. Osl date of soil: obsidian hydration. After obsidian is chipped its surface begins to weather.
