RAMAN SPECTROSCOPIC ESTIMATION OF DEPTH OF DIAMOND ORIGIN: TECHNICAL DEVELOPMENTS AND THE APPLICATION
H. Kagi a , S. Odake a , S. Fukura a , D.A. Zedgenizov b
a Geochemical Laboratory, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
b Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Raman spectroscopy, diamond, inclusions, pressure
Pages: 1183-1187
Abstract
Residual pressure around mineral inclusions in diamond can provide useful information on the depth of diamond origin. Differential stress between an inclusion and host diamond arises from differences in thermal expansion and compressibility between host diamond and minerals. We determined residual pressure around mineral inclusions in a diamond from the Internatsionalnaya Pipe, Yakutia, Russia, using the three-dimensional Raman mapping system developed recently by our group. The maximum residual pressures around the olivine and chromite inclusions were determined to be 0.69 GPa and 0.75 GPa, respectively. We proposed an advanced method for determining simultaneously pressure and temperature conditions where the mineral inclusions were trapped in the host diamond. The obtained values were 3.0 GPa and 447 °C, but these values are lower than typical PT -conditions in the mantle. Several technical possibilities for the discrepancy are discussed.
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