The Experimental Hydration of Obsidian as a Function of Relative Humidity and Temperature

Bibliographic Data

ID2575169
AuthorsJ J Mazer (Argonne National Laboratory), Christopher M Stevenson (0000-0002-3575-2363, Pennsylvania Historical and Museum Commission), W L Ebert (Argonne National Laboratory), J K Bates (Argonne National Laboratory)
Year1991
Volume56
Issue3
Pages504-513
Publication date1991-07-01
Peer ReviewedYes
Open AccessYes
TypeARTICLE
VenueAmerican Antiquity (JOURNAL)
Journal identifiersISSN: 0002-7316 • E-ISSN: 2325-5064
PublisherCambridge University Press (CUP) (PUBLISHER)
DOI10.2307/280898
OpenAlexW1989322435
LanguageEN
Citations received29
References cited15

The experimental hydration of obsidian for up to 30 days is described at relative humidities (RH) of 60, 90, 95, and 100 percent and at temperatures of 150, 160, and 175°C. Under isothermal conditions, the rate of hydration increased by as much as 25 percent between 60 and 100 percent RH. The RH dependence is nonlinear, with the majority of the rate increase occurring between 90 and 100 percent RH. The effect of RH can be related to the driving force for molecular water diffusion in obsidians as described by the chemical potential difference between water sorbed onto the obsidian surface and intrinsic water in the obsidian. The differences in hydration rates caused by RH differences in experiments approximate the error commonly described for obsidian-hydration dating. These results suggest that obsidian-hydration dating requires a knowledge of the site temperature and relative humidity in order to accurately generate age estimates

Diffusion · Humidity · Isothermal process · Mineralogy · Relative humidity · Thermodynamics · Archaeological and Geological Studies · Archaeology and ancient environmental studies · Chemistry · Pleistocene-Era Hominins and Archaeology