Crystallographic analyses of clathrate hydrates included in Vostok ice cores

Abstract

Purpose and methods of crystallographic analyses of clathrate hydrates included in ice cores recovered at Vostok, Antarctica are briefly reviewed. The clathrate hydrate is a crystal composed of a cage structure formed by water molecules, and includes individual air molecules in the molecular cages. We describe the crystallographic structure of the clathrate hydrate crystals found in deep ice cores determined by X-ray diffraction and Raman scattering measurements, and discuss the formation process of the crystals in the ice sheet. We also discuss, as a future prospect in core analysis, what new information and knowledge relating to climatic changes can be deduced from the crystallographic analysis of the clathrate hydrates.