Towards a new method of obsidian hydration dating with secondary ion mass spectrometry via a surface saturation layer approach
Part of : Mediterranean archaeology & archaeometry : international journal ; Vol.2, No.1, 2002, pages 3-20
Issue:
Pages:
3-20
Abstract:
The obsidian hydration dating (OHD) has undergone a considerable evolution, especially with the use of nuclear analysis techniques to accurately determine the hydration rim. We develop a novel approach to the OHD employing certain mathematics of diffusionand making use of available secondary ion mass spectrometry (SIMS) data on obsidians. Our model is based on the non-steady state concentration-dependent diffusion for semi-infinite medium, where diffusion coefficient varies exponentially during diffusion,and for certain initial and boundary conditions the age equation of the obsidian diffusion dating employing SIMS derives from a differential equation that describes diffusion. An essential factor addressing our model is the surface saturation (SS) plateau level at certain depth, which is the result of the diffusion mechanism in the first 1-2 um, the physicochemical factors that address the formation of a surface saturation plateau, the stereochemical structure of obsidian, and certain environmental parameters, naming the method as the obsidian diffusion dating by SIMS (ODDSIMS) - SS approach. The measured data points derive from the H+ concentration-depth profile by SIMS. Application of the present model on available data of well-dated obsidians from the Aegean (Greece), Mexico and USA, provided satisfactory results.
Subject:
Subject (LC):
Keywords:
SIMS, obsidian, dating, diffusion, hydration, Mykonos, Mexico
Notes:
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