This usually requires what is commonly known as a "dating method".
Several dating methods exist, depending on different criteria and techniques, and some very well known examples of disciplines using such techniques are, for example, history, archaeology, geology, paleontology, astronomy and even forensic science, since in the latter it is sometimes necessary to investigate the moment in the past in which the death of a cadaver occurred.
Obsidian Hydration Obsidian is a volcanic glass which has seen a multitude of historical applications.
It can be easily sharpened into a razor-sharp blade, and its uses have included knives, spears, scrapers, saws, drills, and decorative pieces.
Sources: “Dating In Exposed and Surface Contexts”, ed.: Beck, Charlotte. We didn't address dating methods very comprehensively in class, so you definitely add something valuable with this work!
University of New Mexico Press: Albuquerque, NM, 1994.
The Alca sources are among the most extensive sources of obsidian in South America; only the Laguna de Maule source in Chile and Argentina has comparable exposure.
Although the depth of penetration can be measured by various methods, it is generally determined by microscopic examination on thin sections of the artifact cut normal to the surface.Alca is a type of obsidian that is solid and banded black, gray, maroon brown and bottled black maroon brown, that is found in volcanic deposits in the Andes mountains between 3700-5165 meters (12,140-16,945 feet) above sea level.The largest known concentrations of Alca are at the east rim of the Cotahuasi Canyon and in the Pucuncho basin.The glassy material comes in a range of colors from black to green to bright orange, and it is found everywhere rhyolite-rich volcanic deposits are found.Most obsidian is a deep rich black, but, for example, pachuca obsidian, from a source in Hidalgo and distributed throughout Mesoamerica during the Aztec period, is a translucent green color with a golden yellow sheen to it.Relative dating methods are unable to determine the absolute age of an object or event, but can determine the impossibility of a particular event happening before or after another event of which the absolute date is well known.