Air bubble to clathrate hydrate transformation in polar ice sheets: A reconsideration based on the new data from Dome Fuji ice core

Abstract

Mapping the spatial distribution of air bubbles and clathrate hydrates in thick sections of Antarctic ice from Dome Fuji station reveals a considerable redistribution of the inclusions in terms of number and volume in the bubble-to-hydrate transition zone. Analysis of the data indicated that more than 10% of the hydrates nucleated outside the preceding bubbles and more than 30% of the bubbles completely expired due to the gas outflow toward the coexisting hydrates. These features of the gas-hydrate-ice nonequilibrium system are of major importance for modeling the global bubble-to-hydrate transformation in polar ice sheets and thus the results may help improve our ability to extract paleoclimatic information from air inclusions in ice cores. Copyright 2004 by the American Geophysical Union.