Team finds earlier sign of oxygen
From Times Staff and Wire Reports
Oxygen began to appear on Earth millions of years earlier than scientists had thought, researchers reported Friday in the journal Science.
An analysis of a deep rock core from Australia indicates the presence of at least some oxygen 50 million to 100 million years before the great change when the life-giving element began rising to today’s levels. Previously, the earliest indications of oxygen had been from 2.3 billion to 2.4 billion years ago. Before that, the atmosphere was dominated by methane and ammonia.
