Obsidian white dating


Using the end product of diffusion, a phenomenological model has been developed, based on certain initial and boundary conditions and appropriate physicochemical mechanisms, that express the HO concentration versus depth profile as a diffusion/time equation.This latest advance, the novel secondary ion mass spectrometry–surface saturation (SIMS-SS), thus, involves modelling the hydrogen concentration profile of the surface versus depth, whereas the age determination is reached via equations describing the diffusion process, while topographical effects have been confirmed and monitored through atomic force microscopy.In fact, the saturation layer on the surface forms up to a certain depth depending on factors that include the kinetics of the diffusion mechanism for the water molecules, the specific chemical structure of obsidian, as well as the external conditions affecting diffusion (temperature, relative humidity, and pressure).Together these factors result in the formation of an approximately constant, boundary concentration value, in the external surface layer.The FD equations are based on a number of assumptions about the behavior of water as it diffused into the glass and characteristic points of the SIMS H diffusion profile.In Rhodes, Greece, under the direction and invention of Ioannis Liritzis, the dating approach is based on modeling the S-like hydrogen profile by SIMS, following Fick's diffusion law, and an understanding of the surface saturation layer (see Figure).The reliability of the method based on Friedman’s empirical age equation (x²=kt, where x is the thickness of the hydration rim, k is the diffusion coefficient, and t is the time) is questioned from several grounds regarding temperature dependence, square root of time and determination of diffusion rate per sample and per site, apart of some successful attempts on the procedure and applications.


Their initial work focused on obsidians from archaeological sites in western North America.Obsidian hydration dating (OHD) is a geochemical method of determining age in either absolute or relative terms of an artifact made of obsidian.



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