Is Obsidian Hydration Dating Affected by Relative Humidity?

Quaternary Research
By: , and 



Experiments carried out under temperatures and relative humidities that approximate ambient conditions show that the rate of hydration of obsidian is a function of the relative humidity, as well as of previously established variables of temperature and obsidian chemical composition. Measurements of the relative humidity of soil at 25 sites and at depths of between 0.01 and 2 m below ground show that in most soil environments, at depths below about 0.25 m, the relative humidity is constant at 100%. We have found that the thickness of the hydrated layer developed on obsidian outcrops exposed to the sun and to relative humidities of 30-90% is similar to that formed on other portions of the outcrop that were shielded from the sun and exposed to a relative humidity of approximately 100%. Surface samples of obsidian exposed to solar heating should hydrate more rapidly than samples buried in the ground. However, the effect of the lower mean relative humidity experiences by surface samples tends to compensate for the elevated temperature, which may explain why obsidian hydration ages of surface samples usually approximate those derived from buried samples.
Publication type Article
Publication Subtype Journal Article
Title Is Obsidian Hydration Dating Affected by Relative Humidity?
Series title Quaternary Research
DOI 10.1006/qres.1994.1020
Volume 41
Issue 2
Year Published 1994
Language English
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Quaternary Research
First page 185
Last page 190
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