Obsidian dating technique

There has been a renewed interest in the obsidian dating technique which was developed in the early 1960s. In this dating methodology age determination is related to the thickness of hydration layer in the obsidian artifact. The surface of a freshly carved obsidian artifact slowly absorbs moisture and builds up a hydration rim over a period of time. The rate with which the hydration rim is acquired depends greatly on the composition of the obsidian as well as on environmental factors (28,31,59,60, 73-76). 

FIGURE 88 Dating methods. Shortly after the discovery of radioactivity, at the beginning of the twentieth century, it was found that the decay of radioactive elements could be used to keep track of time. Many of the dating techniques developed since then are, therefore, based on radioactive decay phenomena, but others, such as the hydration of obsidian, amino acid racemization, and dendrochronology, are based on other physical, chemical, or biological phenomena. 

Another technique that has been used for dating obsidians, albeit only those that were heated in the past, is the fission track technique (see Textbox 26) (Fleisher et al. 1975). Fission track dating was used, for example, to date the time when an obsidian knifeblade found at a cave in Elmenteita, in Kenya, was heated (see Fig. 24). Since the shape of the blade was distorted, it was deduced that the blade had been heated to a temperature sufficiently high to partially melt it. 

NAA and XRF remain the most widely used techniques for obsidian analysis. However, a wide array of other analytical, geochemical, dating and... 

Obsidian is a volcanic glass frequently used as tool by prehistoric men. The thickness of the hydration layer that has developed on the surface of the artifact since it was made can be used to date it. Measurement of the hydration layer is carried out by a variety of instrumental techniques. Among them are nuclear resonance reactions, LM, PAS, XPS, XANES, sputter-induced optical spectrometry (SIPS), and SIMS [70]. 

This technique is used for dating glassy material like obsidian or any artifacts that contain uranium-bearing material such as natural or human-made glass, ceramics, or stones that were used in hearths for food prepa-... 

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