Did you know that there is strong evidence from several locations for survival of life for at least a million years, both in permafrost and salt deposits. Some scientists have claimed ages as high as 50 million years. This could indeed be a survival strategy for life in order to wait out bad environments, but the time-scales involved are very much less than the age of the Earth (4.56 billion years). Even if an ice or salt deposit is stable, embedded life will eventually be destroyed by natural radioactivity in the Earth's crust. While in this sort of stasis, the life has no mechanisms to repair the molecular damage done by this radiation. The limits for such survival have been estimated at less than a few million years. Source: David Morrison, NASA Astrobiololgy Institute, Senior Scientist.