Obsidian hydration dating archaeology
Chemical analysis of their trace elements now allows most of the sources to be distinguished (especially by neutron activation and x-ray fluorescence spectrometry), so that the pattern of trade spreading out from each can be traced.Two dating methods have been applied to obsidian: it generally went out of favor for everyday purposes (perhaps as a result of competition from metal tools) but it continued to be used for prestige objects in some areas, especially by the Minoans and Mycenaeans.Obsidian has been quarried and traded by western Melanesians since at least 19,000 bp, with the earliest-used and most important source being that at Talasea on CATEGORY: geology DEFINITION: The absorption of water on exposed surfaces of obsidian.In each specific environment, the surface of an obsidian artifact absorbs water at a steady rate, forming the hydration layer. If the local hydration rate is known and constant, this phenomenon can be used as an SYNONYMS OR RELATED TERMS: obsidian hydration layer dating, obsidian dating CATEGORY: technique DEFINITION: A method of dating in which the age of an obsidian artifact is established by measuring the thickness of its (layer of water penetration) and comparing that to a known local hydration rate.
Turning to carbon-14 dating, the archaeologist might discover that the bone dates from 3,500 years ago. It involves putting things into a sequence based on their relative ages.SYNONYMS OR RELATED TERMS: hyalopsite, Iceland agate, mountain mahogany CATEGORY: geology DEFINITION: A jet-black to gray, naturally occurring volcanic glass, formed by rapid cooling of viscous lava.It was often used as raw material for the manufacture of stone tools and was very popular as a superior form of flint for flaking or as it is easily chipped to form extremely sharp edges.Obsidian hydration is not effective on surfaces that are uneven due to gradual weathering caused by natural forces.The volcanic glass of Obsidian Cliff in Yellowstone National Park is a National Historic Landmark, and was an important source of raw material for the manufacture of stone tools by Native Americans.